Rigid Shaft Coupling, 1 Piece Clamp, Inch, Bore Dia. 3/4 in, Steel, Finish Black Oxide, Outside Dia. 1 3/4 in, Overall Length 2 5/8 in, With Keyway, Clearance Dia. 1.75 in, Screw Size 1/4 In.-28, Keyway Width 3/16 in, Max. Torque 1,850 in-lb, Max. RPM 4,000 RPM