This unit comes complete with a 3V 12,000 RPM motor- . It can be stepped down (with the consequent torque multiplication) up to six times as follows: - 12,000 x 12/48 = 3,000RPM - 3,000 x 12/48 = 750RPM - 187.5 x 12/48 = 46.875RPM - 750 x 12/48 = 187.5RPM - 46.875 x 12/48 = 11.72RPM - 11.72 x 12/48 = 2.93RPM Clearly, the motor is fitted with a 12 tooth pinion and the small gear cluster is 12 tooth. The large clusters are all 48 tooth. Not all gears need be used The intermediate output shafts are hardened steel, 3mm dia. Also supplied are press fit pulleys. The whole assembly snaps together. hand tools are almost unnecessary. - Motor can also be varied by changing input voltage but this lowers torque. - motor cage - 40H x 25W x 28Dmm - gearbox cluster - 40W x 25D x 30Hmm - main intermediate shafts - 63 x 3mm Dia mm - Supplied in kit form. DC Voltage : 1.5V Packaged Volume : 0.25l Packaged Weight : 0.05kg Packaged Length : 11cm Packaged Width : 9cm Packaged Height : 2.5cm Gear Material : Plastic Motor Type : Motor + Gearbox Set Motor Nominal Voltage : 3V Max efficiency RPM : 12000RPM