Shaft Collar, System of Measurement Inch, Shaft Locking Type - Couplings 2 Piece Clamp with Keyway, Bore Type - Collars Plain Bore, Bore Dia. 3/4 in, Material - Collars Black Oxide 1215 Lead Free Steel, Outside Dia. 1 1/2 in, Width 1/2 in, Clearance Dia. 1.808 in, Screw Size 1/4 In. -28, Screw Material Alloy Steel, Operating Temp. Range -40 Degrees to 350 Degrees F