Shaft Collar System of Measurement Metric Bore Type Round Bore Diameter 8 mm Bore Thread Size Not Applicable Collar Outside Diameter 20 mm Inside Height to Flat Not Applicable Clearance Diameter 21.5 mm Collar Width 5.5 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