Rigid Shaft Coupling, 1 Piece Set Screw, Inch, Bore Dia. 1/2 in, Aluminum, Finish Plain, Outside Dia. 1 in, Overall Length 1 1/2 in, Without Keyway, Clearance Dia. 1.0 in, Screw Size 1/4 In.-20, Max. Torque 143 in-lb, Max. RPM 3,500 RPM