... :1 stage reduction: 1/3.7 , 1/5.2 2 stages reduction: 1/13.7 , 1/19.2 ,1/26.93 ... stages reduction: 1/50.9 , 1/71.2 ,1/99.5 , ... 1/1394 stages reduction: 1/188 , 1/264 ,1/369 ,1/516 ,1 ... /721 5 stages reduction: 1/699 , 1/977,1/1367, 1/1911,1 ... as following 36mm dc planetary gear box of five reduction stages