A coupling for attaching a fuel canister to an appliance such as a torch comprises a first connector on the canister. The first connector comprises a first set of screw threads where the first set of screw threads are interrupted to define a shape. A second connector on the appliance comprises a locking element. The locking element has a matching shape that matches the shape such that the locking element closely receives the first connector when the first connector is in a first orientation relative to the second connector.