This is the gear motor that moves the router sled in the X/Y plane. It has an internal gear ratio of 158.33:1 (475:3) and has a 6mm output shaft. This is a different sized motor than the original Maslow kits had, and it also has a different gear ratio so configurations will need to be changed in the Ground Control software.
Check the pinout of the encoder to make sure that it fits your application. Wires might need to be swapped to match your controller.