Shaft Collar System of Measurement Metric with Inch Bore Bore Type Round Bore Diameter 5/16 in Bore Thread Size Not Applicable Collar Outside Diameter 25 mm Inside Height to Flat Not Applicable Clearance Diameter 27.3 mm Collar Width 6 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 1-Piece Screw Material Stainless Steel