a device for supplying an alternate gas fuel to a gas - burning apparatus such that the gas - burning apparatus will receive and burn the alternate gas fuel , the gas - burning apparatus being of a type intended to burn a gas fuel which is different from the alternate fuel and is supplied at a pressure substantially different from that of the alternate fuel . the inventive device comprises : an inlet coupling attachable to a discharge fitting provided on the alternate fuel container and an outlet coupling downstream of the inlet coupling and attachable to an inlet fitting provided on the gas - burning apparatus . when the pressure of the alternate gas fuel is significantly greater than that of the intended fuel , the inventive device preferably also includes a restricting element for restricting flow of the alternate fuel through the device from the inlet coupling to the outlet coupling .