When selecting an indoor propane heater with an oxygen shutoff, safety and performance are the top priorities. The Mr. Heater Buddy stands out as the best overall choice for its reliable safety features and portability. For those needing high heating capacity, the VEVOR 100,000 BTU Forced Air Heater offers powerful performance, though at a higher price point. The main tradeoffs involve balancing safety features like oxygen shutoff with heating capacity, size, and cost. Continue reading for a detailed breakdown of each option and how they compare across key factors.
Key Takeaways
- Safety features, especially oxygen shutoff, are a standard but vary in sophistication among models.
- Heater capacity ranges widely, influencing suitability for small rooms versus large spaces.
- Portability and size are important for users who need flexible heating solutions.
- Price often correlates with features—more advanced safety and higher BTU ratings usually cost more.
- Ease of use and maintenance can significantly impact long-term satisfaction with the heater.
| Mr. Heater Buddy 4,000-9,000-BTU Indoor-Safe Portable Propane Radiant Heater |  | Best Overall for Versatile Indoor/Outdoor Use | BTU Range: 4,000-9,000 BTU/hr | Heating Area: 225 square feet | Fuel Type: Propane | VIEW ON AMAZON | See Our Full Breakdown |
| Reznor 30K BTU Propane Garage Heater and Shop Heater – Forced Air Unit |  | Best for Large Indoor Spaces with High Heating Demand | BTU: 30,000 | Efficiency: 82% | Fuel Type: Propane (LP) and Natural Gas | VIEW ON AMAZON | See Our Full Breakdown |
| LAANPOLE 15000BTU Propane Heater with Auto-Shutoff & 3 Heat Settings, Portable Outdoor Heater for Patio, Camping, Garage |  | Best for Outdoor Use and Portable Safety | BTU: 15,000 | Heat Settings: 3 (Low/Medium/High) | Safety Features: Auto-Shutoff, Tip-Over Protection | VIEW ON AMAZON | See Our Full Breakdown |
| Mr. Heater Portable Buddy Radiant Propane Heater |  | Best for Compact Indoor and Outdoor Use | BTU: 9,000 | Heating Area: 225 square feet | Fuel: Propane | VIEW ON AMAZON | See Our Full Breakdown |
| VEVOR Propane Heater, 100,000 BTU Forced Air Portable Garage/Shop Heater with Stepless Temperature Control |  | Best for Large Indoor or Outdoor Spaces with Precise Control | BTU: 100,000 | Heating Area: 2400 sq.ft | Temperature Range: 30°-45° | VIEW ON AMAZON | See Our Full Breakdown |
| Mr. Heater 18,000 BTU Vent Free Radiant Propane Heater |  | Best Overall for Reliable Indoor Heating with Oxygen Safety | BTU: 18,000 BTU/HR | Coverage Area: 700 sq. ft | Fuel Type: Liquid propane | VIEW ON AMAZON | See Our Full Breakdown |
| ProCom Heating Liquid Propane Ventless Infrared Plaque Heater with Base Feet – 10,000 BTU, Thermostat Control |  | Best for Style and Versatile Mounting in Small to Medium Rooms | BTU: 10,000 | Heating Area: 500 sq. ft | Fuel Type: Liquid Propane | VIEW ON AMAZON | See Our Full Breakdown |
| Propane Heater Indoor and Outdoor, 18,000 BTU Patio Heater with Safety Features |  | Best for Portability and Flexibility in Indoor and Outdoor Spaces | Heat Output: 6,000 to 18,000 BTU | Heating Area: Up to 450 sq. ft | Fuel Type: Propane | VIEW ON AMAZON | See Our Full Breakdown |
| VEVOR Propane Heater, 6000 to 18000 BTU Cabinet Heater with 3 Modes, Tip-over & Flameout Protection |  | Best for Adjustable Heat and Long Runtime in Indoor/Outdoor Use | BTU Range: 6,000 to 18,000 | Heating Area: Up to 450 sq. ft | Fuel Type: Propane | VIEW ON AMAZON | See Our Full Breakdown |
| indoor propane heater with oxygen shutoff | Heating Area | Fuel Type | Safety Features | BTU |
|---|---|---|---|---|
| Mr. Heater Buddy 4,000-9,000-B | 225 square feet | Propane | Emergency low oxygen safety system | — |
| Reznor 30K BTU Propane Garage | — | Propane (LP) and Natural Gas | — | 30,000 |
| LAANPOLE 15000BTU Propane Heat | — | — | Auto-Shutoff, Tip-Over Protection | 15,000 |
| Mr. Heater Portable Buddy Radi | 225 square feet | — | Low oxygen safety system | 9,000 |
| VEVOR Propane Heater | 2400 sq.ft | — | — | 100,000 |
| Mr. Heater 18,000 BTU Vent Fre | — | Liquid propane | Low oxygen shut-off | 18,000 BTU/HR |
| ProCom Heating Liquid Propane | 500 sq. ft | Liquid Propane | Oxygen Depletion Sensor (ODS) | 10,000 |
| Propane Heater Indoor and Outd | Up to 450 sq. ft | Propane | ODS & Tip-over Protection | — |
| VEVOR Propane Heater | Up to 450 sq. ft | Propane | — | — |
More Details on Our Top Picks
Mr. Heater Buddy 4,000-9,000-BTU Indoor-Safe Portable Propane Radiant Heater
This heater stands out for its portability and safety features, making it a flexible choice for both indoor and outdoor spaces. Compared with the larger Vevor 100,000 BTU, it offers a more manageable size but with significantly less heating capacity. Its dual heat settings allow for quick adjustments, which is ideal for small to medium rooms, though its runtime on a 1 lb propane cylinder is limited, requiring frequent refills. The safety system, including an emergency low oxygen shutoff, enhances confidence in indoor use. However, proper ventilation remains essential, and misuse of accessories can void the warranty. This model is best suited for users needing a portable, safe heater for small spaces or occasional outdoor use.
Pros:- Adjustable heat output with two temperature settings
- Safe for indoor and outdoor use with safety features
- Portable and easy to operate
Cons:- Limited run time on a 1 lb propane cylinder
- Requires proper ventilation for indoor use
- Use of unauthorized accessories voids warranty
Best for: Individuals seeking a safe, portable heater for small indoor or outdoor areas
Not ideal for: Large spaces or long-term heating needs where extended runtime is crucial
- BTU Range:4,000-9,000 BTU/hr
- Heating Area:225 square feet
- Fuel Type:Propane
- Run Time:5.4 hours on low, 2.4 hours on high
- Safety Features:Emergency low oxygen safety system
- Materials:Self-extinguishing materials
Our verdict“This heater is an excellent choice for users needing a portable, safe solution for small spaces with flexible indoor/outdoor use.”
Reznor 30K BTU Propane Garage Heater and Shop Heater – Forced Air Unit
This heavy-duty heater delivers a substantial 30,000 BTU, making it ideal for expansive garages, workshops, or warehouses. It surpasses the smaller Mr. Heater Buddy in capacity but is less portable and more suited to fixed installation. Its versatile mounting options, including ceiling or wall, allow for flexible placement, while the included LP conversion kit supports propane use. The high efficiency of 82% maximizes fuel economy for large, well-ventilated indoor areas. Nonetheless, it requires proper venting and mounting brackets sold separately, which adds to setup complexity. This heater is best for commercial or large residential spaces where sustained, high-capacity heating is needed.
Pros:- High heating capacity with 30,000 BTU
- Versatile mounting options for different spaces
- Includes LP conversion kit for propane
Cons:- Mounting brackets sold separately
- Requires proper venting setup
- Limited to indoor use
Best for: Workshop or warehouse owners needing high-capacity, fixed indoor heating solutions
Not ideal for: Small rooms or users seeking portable heating options
- BTU:30,000
- Efficiency:82%
- Fuel Type:Propane (LP) and Natural Gas
- Mounting Options:Ceiling or wall mount (mounting sold separately)
- Includes:LP conversion kit
Our verdict“This heater is well-suited for large, fixed indoor spaces requiring powerful, sustained heat, but less so for portable or small-area applications.”
LAANPOLE 15000BTU Propane Heater with Auto-Shutoff & 3 Heat Settings, Portable Outdoor Heater for Patio, Camping, Garage
This heater balances power with portability, providing 15,000 BTU and three adjustable settings for outdoor and semi-outdoor environments. Its safety features, including auto-shutoff and tip-over protection, make it a reliable choice for patios, camping, or garage use. Compared to the Mr. Heater Buddy, it offers higher heat capacity and more safety features, making it better suited for outdoor settings where safety is critical. However, it requires a propane cylinder connection and may pose safety concerns if not used properly outdoors. Its durable construction withstands outdoor conditions, but it’s limited to ventilated areas, not suitable for enclosed indoor spaces without adequate ventilation.
Pros:- Powerful 15,000 BTU with three heat settings
- Built-in safety features including auto-shutoff
- Durable and portable for outdoor use
Cons:- Requires connection to propane cylinder
- Potential safety concerns if used improperly outdoors
- Limited indoor use without ventilation
Best for: Outdoor enthusiasts or those needing a portable heater for patios or camping
Not ideal for: Indoor spaces lacking proper ventilation or users seeking a heater for small indoor rooms
- BTU:15,000
- Heat Settings:3 (Low/Medium/High)
- Safety Features:Auto-Shutoff, Tip-Over Protection
- Material:Heavy-duty aluminum
- Weight:Lightweight
Our verdict“Ideal for outdoor use where portability and safety features are priorities, but not suitable for enclosed indoor spaces.”
Mr. Heater Portable Buddy Radiant Propane Heater
This model offers up to 9,000 BTU, providing a reliable, portable option for small indoor or outdoor areas. It closely resembles the Mr. Heater Buddy 4,000-9,000 BTU but emphasizes portability and efficiency. Its dual heat settings and safety features support flexible use, though its runtime on a 1 lb cylinder is limited, making it less suitable for long-term heating. Proper ventilation remains a necessity, and misuse can compromise safety. Its compact size makes it ideal for quick heating in small spaces, but it isn’t designed for larger areas or prolonged operation without frequent refills.
Pros:- Portable and suitable for indoor and outdoor use
- Multiple heat settings with safety features
- Efficient fuel consumption
Cons:- Requires 1 lb propane cylinder which needs frequent replacement
- Limited runtime for continuous heating
- Use of un-authorized accessories voids warranty
Best for: Individuals needing a portable, small-space heater for occasional indoor/outdoor use
Not ideal for: Large rooms or continuous heating needs due to limited runtime
- BTU:9,000
- Heating Area:225 square feet
- Fuel:Propane
- Run Time:2.4 to 5.4 hours
- Safety Features:Low oxygen safety system
- Temperature Settings:Low and high
Our verdict“A practical, portable heater for small spaces and quick heating, but not suited for extended use or large areas.”
VEVOR Propane Heater, 100,000 BTU Forced Air Portable Garage/Shop Heater with Stepless Temperature Control
This heater’s massive 100,000 BTU output makes it the go-to for heating expansive areas like garages or outdoor zones. It exceeds the capacity of the Mr. Heater Buddy and LAANPOLE for large-scale heating, with stepless temperature control offering precise adjustments. Its dual safety features—overheat and flameout protection—add reassurance during extended operation. Its weatherproof, rugged design and ergonomic handle facilitate mobility, and it supports large propane tanks, reducing refills. However, it demands a large tank and appropriate venting, limiting its practicality for small or enclosed spaces. This model caters to those needing powerful, adjustable heating over large areas, especially in outdoor or semi-outdoor environments.
Pros:- Powerful 100,000 BTU heating capacity
- Stepless temperature control for precision
- Dual safety protections and weatherproof design
Cons:- Requires large propane tank for operation
- Limited run time per tank, may need frequent refills
- Not suitable for small or enclosed indoor spaces
Best for: Large garage or outdoor area owners needing powerful, adjustable, and portable heating
Not ideal for: Small indoor rooms or users seeking a lightweight, compact heater
- BTU:100,000
- Heating Area:2400 sq.ft
- Temperature Range:30°-45°
- Weight:18.96 lbs
- Fuel Tank Size:20 lbs
- Run Time:4.4-6.2 hours
- High Altitude Support:up to 4921 ft
Our verdict“Perfect for large-scale, adjustable heating in outdoor or expansive indoor environments, with a need for large tanks and proper venting.”
Mr. Heater 18,000 BTU Vent Free Radiant Propane Heater
This heater stands out for its high heat output of 18,000 BTU, capable of warming spaces up to 700 sq. ft., making it ideal for larger rooms. Unlike the ProCom Infrared Heater, which offers less heat but more compact design, this model provides robust warmth suitable for bigger areas. Its vent-free operation and built-in thermostat make it user-friendly, especially during power outages since no electricity is required. The low oxygen shut-off adds a safety layer, but users must follow strict ventilation guidelines. The tradeoff is that it lacks an integrated blower, which can limit airflow distribution. This pick makes the most sense for those needing dependable, high-capacity indoor heat with safety features without relying on power.
Pros:- Provides ample heat for spaces up to 700 sq. ft.
- No electricity required, ensuring operation during outages
- Built-in thermostat for consistent temperature control
Cons:- Blower fan kit sold separately, which can limit airflow customization
- Requires propane fuel and proper ventilation for safe indoor use
Best for: Homeowners seeking reliable, high-capacity indoor heat for large living areas during power outages
Not ideal for: Small apartments or rooms under 300 sq. ft., where the large size and high BTU might be overkill
- BTU:18,000 BTU/HR
- Coverage Area:700 sq. ft
- Fuel Type:Liquid propane
- Venting:Vent free
- Ignition:Electronic
- Safety Features:Low oxygen shut-off
Our verdict“Ideal for large indoor areas needing dependable heat with safety features, but requires careful ventilation and additional accessories.”
ProCom Heating Liquid Propane Ventless Infrared Plaque Heater with Base Feet – 10,000 BTU, Thermostat Control
Compared with larger models like the Mr. Heater 18,000 BTU, this ProCom heater provides a more modest 10,000 BTU, making it suitable for bedrooms or living rooms up to 500 sq. ft. Its compact infrared design ensures quick, focused warmth, and the modern aesthetic blends well with residential interiors. The built-in thermostat and multiple mounting options (wall or floor) add convenience, especially over the VEVOR Propane Heater which emphasizes portability over style. Safety features include an oxygen depletion sensor, providing peace of mind. The tradeoff is its lower heat output, which might not suffice for larger or drafty spaces. This heater makes sense for users prioritizing aesthetics, space savings, and moderate heating needs.
Pros:- Stylish, modern design fits seamlessly into home interiors
- Versatile mounting options for flexibility in placement
- No electricity needed, ideal for power outages
Cons:- Limited to 10,000 BTU, less effective for larger or drafty rooms
- Requires propane fuel, which must be purchased separately
Best for: Homeowners needing a stylish, space-efficient heater for small to medium rooms with safety features
Not ideal for: Large open-plan areas or spaces exceeding 500 sq. ft., where higher BTU is necessary
- BTU:10,000
- Heating Area:500 sq. ft
- Fuel Type:Liquid Propane
- Control:Thermostat
- Safety Features:Oxygen Depletion Sensor (ODS)
- Mounting Options:Wall or Floor
Our verdict“Great for stylish, space-saving heating in small to medium rooms, but not suitable for large or very cold spaces.”
Propane Heater Indoor and Outdoor, 18,000 BTU Patio Heater with Safety Features
This heater offers a flexible solution with adjustable heat settings up to 18,000 BTU, suitable for spaces up to 450 sq. ft., making it stand out for its portability and outdoor versatility. Unlike the fixed installation of the Mr. Heater 18,000 BTU Vent Free, this unit is designed for mobility, with a lightweight frame and handles. Its safety features include automatic shut-off for low oxygen and tip-over, comparable to the VEVOR Propane Heater, but with the added advantage of being usable both indoors and outdoors. The tradeoff is that it requires a 20-pound propane tank, which is not included, and its heating coverage is slightly less. This makes it ideal for users who want a portable, multi-use heater for patios, garages, or occasional indoor use.
Pros:- Adjustable heat output for customized comfort
- Portable and lightweight for easy transport
- No electricity needed, reducing reliance on power sources
Cons:- Requires a separate purchase of a 20lb propane tank
- Effective for spaces up to 450 sq. ft., less than larger models
Best for: People needing a portable heater for both indoor and outdoor use, especially in patios or garages
Not ideal for: Large indoor spaces or permanent heating solutions where high BTU capacity is needed
- Heat Output:6,000 to 18,000 BTU
- Heating Area:Up to 450 sq. ft
- Fuel Type:Propane
- Run Time:Up to 69 hours
- Safety Features:ODS & Tip-over Protection
- Power:No electricity required
Our verdict“Perfect for portable heating needs in both indoor and outdoor settings, with safety features to prevent accidents, but limited coverage for larger rooms.”
VEVOR Propane Heater, 6000 to 18000 BTU Cabinet Heater with 3 Modes, Tip-over & Flameout Protection
Compared with the Mr. Heater 18,000 BTU Vent Free, this VEVOR heater offers a stepless temperature control from 6,000 to 18,000 BTU, providing more precise adjustment for diverse needs. Its portability, with locking wheels and a compact footprint, makes it suitable for both indoor and outdoor spaces, similar to the Propane Heater Indoor and Outdoor. Safety features like tip-over and flameout protection enhance reliability, especially in outdoor settings or semi-permanent indoor placements. The longer runtime of up to 73 hours on a 20 lb tank ensures extended operation. The tradeoff is that it requires handling propane tanks and proper ventilation, which might be a concern for some users. This model is well-suited for those who value adjustable heat and long-lasting performance in versatile environments.
Pros:- Stepless temperature control for fine-tuned heating
- Long runtime of up to 73 hours, reducing refueling needs
- Mobility with locking wheels for versatile placement
Cons:- Requires propane tank setup and handling
- Limited to areas up to 450 sq. ft, less coverage than larger heaters
Best for: Users seeking precise, adjustable heating with safety protections for outdoor or semi-permanent indoor use
Not ideal for: Small spaces under 200 sq. ft. or users who prefer plug-in electric solutions for convenience
- BTU Range:6,000 to 18,000
- Heating Area:Up to 450 sq. ft
- Fuel Type:Propane
- Tank Capacity:20 lbs
- Run Time:Up to 73 hours
- Protection Features:Tip-over & Flameout
Our verdict“Excellent for those who need adjustable, long-lasting propane heat in portable form, but requires handling tanks and proper ventilation.”
How We Picked
To evaluate these indoor propane heaters with oxygen shutoff, I focused on safety features, especially the reliability and type of oxygen shutoff mechanism. Performance metrics like BTU output and heating area were key, ensuring the heater can comfortably warm the intended space. Build quality, ease of operation, and maintenance considerations also played a role, along with value for money. These products were ranked to prioritize safety and effectiveness, with a balance of affordability and premium features to cater to different buyer needs.| indoor propane heater with oxygen shutoff | Fuel Type | Safety Features |
|---|---|---|
| Mr. Heater Buddy 4,000-9,000-B | Propane | Emergency low oxygen safety system |
| Reznor 30K BTU Propane Garage | Propane (LP) and Natural Gas | — |
| LAANPOLE 15000BTU Propane Heat | — | Auto-Shutoff, Tip-Over Protection |
| Mr. Heater Portable Buddy Radi | — | Low oxygen safety system |
| VEVOR Propane Heater | — | — |
| Mr. Heater 18,000 BTU Vent Fre | Liquid propane | Low oxygen shut-off |
| ProCom Heating Liquid Propane | Liquid Propane | Oxygen Depletion Sensor (ODS) |
| Propane Heater Indoor and Outd | Propane | ODS & Tip-over Protection |
| VEVOR Propane Heater | Propane | — |
Factors to Consider When Choosing Indoor Propane Heater With Oxygen Shutoff
Choosing the right indoor propane heater with oxygen shutoff involves assessing several critical factors. Safety features must be robust, especially if the heater will operate in enclosed spaces. Heating capacity should match the size of the area you intend to warm, avoiding undersized or oversized units. Portability can be important if you need to move the heater frequently, but larger units offer higher power for bigger spaces. Additionally, consider ease of use, maintenance needs, and overall build quality to ensure long-term satisfaction. Price can vary widely, so balancing features with budget is essential.Safety Features and Oxygen Shutoff Mechanisms
Safety is paramount when choosing an indoor propane heater. An oxygen shutoff system automatically turns off the heater if oxygen levels drop below a safe threshold, reducing the risk of carbon monoxide buildup. Look for units with proven safety certifications and reliable shutoff technology. Some models feature electronic sensors, while others use mechanical systems. The right choice depends on your safety priorities and the environment where the heater will operate. Never compromise on safety features for cost savings, especially in enclosed spaces.
Heating Capacity and Area Coverage
Matching the heater’s BTU rating to your space size prevents inefficiency and unsafe operation. Smaller rooms may only need a heater with around 10,000 BTUs, while larger garages or workshops could require 30,000 BTUs or more. Overestimating capacity can lead to unnecessary energy consumption, while underestimating risks insufficient warmth and safety. Always measure your space accurately and choose a model that provides adequate heating without excessive power, which can cause safety concerns or higher utility bills.
Portability and Size
If you plan to move the heater between different spaces, portability features like wheels and compact design become important. Smaller units tend to be easier to handle, but may have limited heating power. Larger, higher-capacity models are often bulkier and less mobile but deliver more consistent heat for bigger areas. Consider your mobility needs carefully— a lightweight, portable heater offers flexibility, but a stationary unit might be more durable and efficient for fixed installations.
Ease of Use and Maintenance
User-friendly controls, clear instructions, and straightforward maintenance are essential for ongoing safe operation. Some heaters feature digital thermostats and remote controls, making temperature adjustments simple. Regular cleaning of vents and filters prolongs the lifespan and maintains safety. Check for access to replaceable parts and clear safety warnings. A model with intuitive operation reduces the risk of misuse and enhances safety, especially important in enclosed indoor environments.
Price and Value
Prices vary based on capacity, safety features, and brand reputation. While budget models may save money upfront, they can lack advanced safety features or durable build quality, leading to higher long-term costs. Investing in a slightly more expensive unit with reliable oxygen shutoff and robust construction often pays off in safety and longevity. Consider your budget in relation to your space requirements and safety needs, and avoid sacrificing critical safety features for lower cost.
Frequently Asked Questions
Can I use an indoor propane heater with oxygen shutoff in a basement?
Using an indoor propane heater with oxygen shutoff in a basement can be safe if the unit is designed for enclosed spaces and has reliable safety features. The oxygen shutoff reduces the risk of carbon monoxide buildup, which is a primary concern in underground or poorly ventilated areas. However, it’s essential to ensure proper ventilation and follow manufacturer instructions. Regularly check the sensor functions and keep a carbon monoxide detector nearby for added safety.
How often should I inspect the oxygen shutoff system on my heater?
It’s advisable to inspect the oxygen shutoff system before each use to verify proper operation. Many units include self-diagnostic features that alert you to malfunctions. Regular maintenance, such as cleaning sensors and checking connections, ensures reliability. If you notice any irregularities or warning signals, stop using the heater immediately and have it serviced. Proper inspection and maintenance are critical for ensuring ongoing safety and effective operation.
What is the typical lifespan of an indoor propane heater with oxygen shutoff?
The lifespan of these heaters varies based on brand, usage, and maintenance. On average, a well-maintained unit can last 5 to 10 years. Regular servicing, such as cleaning and replacing worn parts, extends functional life. Investing in reputable brands with quality safety features often results in longer durability. Keep in mind that safety sensors may need periodic calibration or replacement to maintain effectiveness over time.
Are portable propane heaters with oxygen shutoff suitable for large spaces?
Portable models with oxygen shutoff are generally best suited for small to medium-sized rooms or spaces like garages and workshops. For larger areas, higher BTU units or stationary heaters provide more consistent warmth. Portable units are convenient but may struggle to evenly heat large or open spaces. If a portable heater is your only option, choose one with higher BTU ratings and consider supplemental heating methods for optimal safety and comfort.
Can I leave my indoor propane heater with oxygen shutoff running overnight?
Leaving a propane heater with oxygen shutoff running overnight is possible if it is designed for continuous operation and has reliable safety features. However, it’s best practice to turn off heaters when not in use or when sleeping, especially in enclosed spaces. Always ensure proper ventilation and have a carbon monoxide detector installed. Regular maintenance and sensor checks are essential to prevent malfunctions during extended use.
Conclusion
For most buyers, the Mr. Heater Buddy offers the best combination of safety, portability, and ease of use, making it ideal for smaller spaces and general household safety. Those with larger areas or high heating demands might prefer the VEVOR 100,000 BTU Forced Air Heater, despite its higher price, for its powerful output. Budget-conscious users can consider models with basic safety features but should prioritize units with proven oxygen shutoff systems. Beginners should focus on units with simple controls and clear safety certifications, while experienced users may opt for premium models with advanced features. Overall, safety and proper matching to your space remain the guiding principles in choosing the best indoor propane heater with oxygen shutoff.
