The invention relates to a hub for bicycles and the like, comprising a hub axle and a hub housing concentrically mounted in relation thereto including a bearing device having at least two bearings mounted between the axle and the housing. In particular, it relates to extending the life of the modulator by shifting the set of elements used, without physically replacing the micro-mechanical light modulator. In both embodiments, a current sink is used. The plate is secured directly over the top of the carburetor, and extends radially outward to provide a larger area for securing its fiberglass housing. After multiple repetitions of the irradiation procedure, the amorphous silicon film formed on a substrate is completely transformed into a polysilicon film. The apparatus includes a microphone for receiving audio signals, a left loudspeaker for outputting a left audio signal, a right loudspeaker for outputting a right audio signal, a touch input unit for receiving a user’s operating signals to control a mobile device, and a plug.