Quick Clamping Shaft Collar, System of Measurement Metric, Bore Type Round, Bore Diameter 20 mm, Bore Thread Size Not Applicable, Collar Outside Diameter 40 mm, Inside Height to Flat Not Applicable, Collar Width 15 mm, Collar Material Plastic, Keyway Width Not Applicable, Collar Material Grade Acetal, Keyway Depth Not Applicable, Center to Lever Top 38.8 mm, Collar Construction 1-Piece, Screw Material Stainless Steel, Resistance Properties Corrosion Resistant, Screw Seating Torque 2.8 N-m