A planetary gear type gearbox includes a front-stage transmission section and rear-stage transmission section. 5 gcm3 and ii) abrasive grains having pores. An input pad receives an input signal from a user that initiates a count-down sequence. A gas generator and absorber can be housed in the cell for generating the control pressure. The anode fuel supply unit having a fuel comprises at least one fuel input port for receiving a resupplied fuel and at least one cathode gas input port for receiving the cathode gas from the gas exit. The device allows the metal strings of, for example, a guitar to be readily cleaned in-situ while on the instrument to maintain the brightness of tone of the string.