"Celestron Motodec #94141 Fits Ulimate and Classic" C8's. Made by JMI for Celestron. Fits on fork mounts with 1/8 inch threaded rods on the Dec tangent arm. May not fit on some early C8's, some of which use 3/16 inch threaded rods.
This is the motor, hardware for attaching it, and instruction sheet.