Shaft Collar, System of Measurement Inch, Bore Type Round Keyed, Bore Diameter 1 in, Bore Thread Size Not Applicable, Collar Outside Diameter 1 3/4 in, Inside Height to Flat Not Applicable, Clearance Diameter 2.03 in, Collar Width 1/2 in, Collar Material Carbon Steel, Keyway Width 1/4 in, Collar Material Grade 1215, Keyway Depth 1/8 in, Thread Direction Not Applicable, Center to Lever Top Not Applicable, Collar Construction 2-Piece, Screw Material Alloy Steel, Screw Material Finish Black Oxide This product contains a chemical that is regulated under California Proposition 65. Warning: This product contains a chemical known to the State of California to cause cancer. Warning: This product contains a chemical known to the State of California to cause birth defects or other reproductive harm. - Nickel (Metallic)