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 - Supplied in kit form.