Butane fuel cartridge. Provides the fuel-efficient heat source you need and the safety features you deserve. Each 8-ounce butane cartridge supplies up to 4-hours of burning performance. Features a unique dual safety system. Temperature Sensing Valve (TSV) automatically shuts off the flame if in danger of over-heating. Rim Vent Release feature (RVR) protects unused cans against over-pressurizing. Compatible with Sterno butane appliances and stoves that accept a standard 8-ounce butane cartridge.