A refillable external dosing valve for use in dispensing a hydrocarbon fuel for a gas auto-feed drive tool. The re-fillable dosage valve includes an entry point ( 5 ) and a non-return valve so that a fuel canister ( 2 ) is able to be reloaded after the fuel bag internally of the canister has been totally deflated. The valve is adapted to engage the canister in a manner allowing the valve to establish fluid communication with the fuel in the canister and co-operate with a refilling nozzle of apparatus adapted to deliver a substance from a reservoir through the dosing valve to refill a receptacle with said substance. The valve is also configured to include an internal metering chamber which enables a predetermined amount of fuel to be delivered to a metering chamber within the gas auto-feed drive tool. Residual gas within the canister can also be removed when the canister is to be disposed of.
