Shaft Collar, System of Measurement Inch, Shaft Locking Type - Couplings 2 Piece Clamp, Bore Type - Collars Plain Bore, Bore Dia. 1 7/8 in, Material - Collars Aluminum, Outside Dia. 2 7/8 in, Width 11/16 in, Clearance Dia. 3.187 in, Screw Size 5/16 In. -24, Screw Material Steel, Operating Temp. Range -40 Degrees to 220 Degrees F