Solar Motor & Gearbox Kit. The gearing is 9:1 or 27:1 with approximately 75 or 25rpm at 0.5 Volts. Glue is needed to complete this pack (eg. Bostik all purpose or an instant glue). Contents: solar motor, PVC-gears, diameter 2 mm shaft and housing. Size (without motor): diameter 36 x 15mm.