Countersunk Washer, Material Grade/Class Not Graded, Material Steel, Finish Black Oxide, For Screw Size M4, Maximum Inside Diameter 4.3 mm, Outside Diameter 16 mm, Countersink Angle 90 Degrees , Overall Height 3 mm, System of Measurement Metric, Color Black, For Use With Flat and Oval Head Screws, Industry Standards AMPG 2002 FIN.31, Pack Size Small Pack, Rockwell Hardness C40, Thickness Tolerance +/-0.3 mm, Package Quantity 5