A method, system, and device provide power-efficient communications within the context of available power. The transmission includes four planetary gear sets having seven torque-transmitting mechanisms and three fixed interconnections. The apparatus further includes an internal locking arrangement configured to selectively couple and decouple the upper body portion and the mandrel. In another embodiment, the hearing aid housing is manufactured with an integrated face plate. The resistance of the surface layer is smaller than that of the elastic layer so that the entire volume resistance of the roll is less than a volume resistance of the elastic layer. The toy water gun includes a trigger to actuate the switch.