Shaft Collar, System of Measurement Metric, Bore Type Round, Bore Diameter 8 mm, Bore Thread Size Not Applicable, Collar Outside Diameter 18 mm, Inside Height to Flat Not Applicable, Clearance Diameter 22.4 mm, Collar Width 9 mm, Collar Material Stainless Steel, Keyway Width Not Applicable, Collar Material Grade 303, Keyway Depth Not Applicable, Thread Direction Not Applicable, Center to Lever Top Not Applicable, Collar Construction 2-Piece, Screw Material Stainless Steel 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. -