Choice of gear ratios: 12.7: 1, 38.2:1, 114.7:1, 344.2:1 Includes motor cover and crank arm. Case and gear made from durable plastic. Includes FA-130 type motor. Offering a double gearbox perfect for use in amateur robot contests, this gearbox is suitable for use with remote controlled robots. Choice of 4 gear ratios, offers emphasis on speed or power to suit your needs. Left/right independent design means you can set different gear ratios for either side.