Keyed Shaft Collar, System of Measurement Metric, Bore Type Round Keyed, Bore Diameter 50 mm, Bore Thread Size Not Applicable, Collar Outside Diameter 78 mm, Inside Height to Flat Not Applicable, Clearance Diameter 84.7 mm, Collar Width 19 mm, Collar Material Carbon Steel, Keyway Width 14 mm, Collar Material Grade 1215, Keyway Depth 4 mm, Thread Direction Not Applicable, Center to Lever Top Not Applicable, Collar Construction 2-Piece, Screw Material Alloy Steel, Screw Material Finish Black Oxide WARNING: This product can expose you to chemicals including Ethylene thiourea, which is known to the State of California to cause cancer and birth defects or other reproductive harm. For more information go to www.P65Warnings.ca.gov. -