Rigid Shaft Coupling, 1 Piece Clamp, Inch, Bore Dia. 1/2 In., Steel, Finish Black Oxide, Outside Dia. 1-3/8 In., Overall Length 1-3/8 In., With Keyway, Clearance Dia. 1.375 In., Screw Size #8-32, Keyway Width 1/8 In., Max. Torque 450 in.-lb., Max. RPM 4000