Gas refill adapter It's only about 5g,so u can carry it easily when u go hiking and camping. With this adapter,u canrefill your gas canister in a similar fashion that you would a gas cigarette lighter. U willsave quite a bit of money by refilling How to use it Weighing unused full butane canister and write with felt-tip on the base. Place empty canister to be refilled in freezer for approx. half hour. Take canister from freezer and place adaptor onto the canister. Take your new full butane canister and insert into adaptor. Push canister firmly down about 10-15 seconds at a time, checking each time the weight of the canister. Material:Copper Specification: 17 x8mm Warning: Considering safety,the refill canister weight should lighter than the original canister! After you have refilled the canister it is always good safety practice to check the seal on the canister for no leaks! Only refill your canisters in a well ventilated area, i.e. outdoors! Note:Not including the gas tank!