Flat Washer Flat Washer Type Standard Dimensional Standards ASME B18.21.1-2009 (R2016) Material Steel Material Grade/Class Grade 2 Finish Zinc Plated For Screw Size 1 1/2 in Inside Diameter 1.563 in Outside Diameter 3 in Maximum Thickness 0.156 in System of Measurement Inch Minimum Thickness 0.156 in Color Silver Pack Size Small Pack RoHS Compliant Yes Package Quantity 21