... ,17.5,21.5,26Kgf-cm torque reduction ratio:from1/3.4 to 1/1975 28mm diameter low noise gearbox Model ... : gearbox length(mm)stadgereduction ratio 34.1 3.4,3.8,4.4,5.3,6.742.7 12,13,15,16,18 ... ,19,20,23,26,28,35,4551.3 40,45,50,56,65,74,85,95,102,106 ...