Iwatani 8 oz. Butane Canisters are produced under the most stringent quality controls possible. Each Iwatani BU-6 canister is listed to UL 147B and complies with the Department of Transportation requirements for DOT 2P cylinders. The Iwatani canisters are equipped with the patented Countersink Release Vent (CRV) system for maximum safety. If the pressure in the canister becomes abnormally high, the CRV activates and releases the pressure. All Iwatani butane powered appliances must be used with the Iwatani brand butane fuel to ensure the maximum safety and performance.