Please visit my eBay store to see a huge selection of different gearheads and gear motors. 

For sale is a very large robust gearhead for a stepper motor or a servo motor. The ratio is 20 to 1 reduction. This unit comes complete with a key for the keyway and the mounting hardware to attach your stepper motor to the gearhead. 

Please note that any measuring instruments are for illustration purposes only and are not part of the sale. If you pay by noon Eastern time I will mail the unit the very same day by priority mail.