2 in, Hub Material Aluminum, Dynamic Torque Reversing 212.7 in, Maximum Bore Diameter 1 in.8 in, Dynamic Torque Non-Reversing 425 in-lb, Hub Length 1.5 in-lb, Coupling Outside Diameter 2 3/4 in, Number of Discs 2 with Center Spacer, Center Spacer Material Aluminum, Length Through Bore 1 1.