AmpFlow wheel motors combine a motor, a gearbox, and a wheel into one easy-to-use unit. The AmpFlow speed reducer is a heavy-duty, low-cost, gearhead that works with any of the three-inch diameter AmpFlow motors. The reduction ratio is 8.3:1. The backlash is about +/- 1.2 degrees, and the gearhead has been tested to a failure point of 3500 inch-pounds, (395 Nm), of torque. Four long 1/4-20 mounting bolts are supplied with the unit. The AmpFlow reversible motors are made from two sturdy aluminum castings and a seamless body. There is a short 3/8-inch diameter shaft on the rear of the motor for mounting an optical encoder. The motor is finished in a high-quality black powder-coat. The combination of high power, high traction, and light weight make these wheel motors ideal for robots and other mobile applications. The AmpFlow wheel/gearmotor combination can be configured with your choice of six different wheel sizes and six different motors. Search Amazon for "AmpFlow WheelMotors". The motors, gearmotors, and wheels are also available separately.