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EN 417 is a European Standard concerning non-refillable metallic cartridges for liquefied petroleum gases. The standard specifies material, construction, inspection and marking requirements for cartridges with or without a valve, for use with portable appliances which comply with the requirements of EN 521.
The term is used colloquially to refer to cartridges with the 7/16" UNEF threaded valve used on disposable butane and butane/isobutane/propane mix cartridges used in some backpacking stoves. The correct name for this is Lindal B188 valve, the manufacturer's designation. This informal use is improper, as the EN 417 standard applies also to cartridges that do not have a Lindal valve, such as the valveless pierceable Epigas canisters often used in Europe.
The Lindal valve, unlike of course a pierceable canister, should seal itself if the fuel container is unscrewed from the equipment to which it is attached. However, the self-sealing action cannot be relied upon as a safety feature.[clarification needed]