Rigid Shaft Coupling, 1 Piece Clamp, Inch, Bore Dia. 1 3/4 in, Steel, Finish Black Oxide, Outside Dia. 3 7/16 in, Overall Length 3 7/16 in, With Keyway, Clearance Dia. 3.438 in, Screw Size 5/16 In.-24, Keyway Width 3/8 in, Max. Torque 8,310 in-lb, Max. RPM 4,000 RPM