The metal gears have better wear and tear properties. Gearbox is sealed and lubricated with lithium grease and requires no maintenance. Although motor gives 13.5 RPM at 12V, motor runs smoothly from 4V to 12V and gives the wide range of RPM, and torque. The shaft has a hole for better coupling. Operating Voltage(V): 12 Rated Torque(kg-cm): 15.7 Stall Torque(kg-cm): 52
