The present invention is directed to a fuel supply adapted to be connected to a host device, such as an electronic device powered by a fuel cell. The fuel supply comprises a front face and at least one functional element, wherein the at least one functional element is positioned relative to a datum defined on the front face. The front face is positioned opposite to a corresponding face on the host device, and the datum matches a matching datum on the host device and the at least one functional element is connected to corresponding connection on the host device. An adapter is also provided.