Rigid Shaft Coupling, One Piece Clamp Type, Without Keyway, Bore Dia. 3/16 In., Overall Length 7/8 In., Outside Dia. 9/16 In., Clearance Dia. (In.) 0.651, Clearance Dia. (mm) -, Screw Size (In.) #2-56, Screw Size (mm) -, Keyway Width (In.) -, Keyway Width (mm) -, Max. Torque (In.-Lbs.) 60, Black Oxide 1215 Steel, Lead Free Material