The Lynxmotion Quadrature Motor Encoder V2 (w/Cable) is designed for the 12VDC, 200rpm, 0.78Kg-cm GHM-16 (w/ rear shaft) and 7.2VDC 291RPM 11oz-in GHM-03 Spur Gear Head Motor (w/ Rear Shaft) , sold separately. The original V1 encoder was discontinued, while the replacement does not properly fit over the plastic around the rear shaft, so a lexan spacer and tape is included.