Mountable Shaft Collar, System of Measurement Metric, Bore Type Round, Bore Diameter 30 mm, Bore Thread Size Not Applicable, Collar Outside Diameter 54 mm, Inside Height to Flat Not Applicable, Clearance Diameter 59.2 mm, Collar Width 15 mm, Collar Material Aluminum, Keyway Width Not Applicable, Collar Material Grade 2024, Keyway Depth Not Applicable, Thread Direction Not Applicable, Center to Lever Top Not Applicable, Collar Construction 2-Piece, Screw Material Alloy Steel 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. -