Flat Washer Flat Washer Type Standard Dimensional Standards ANSI B18.22.1 Material PEEK Material Grade/Class Grade 2 Finish Plain For Screw Size M18 Inside Diameter 19 mm Outside Diameter 34 mm Maximum Thickness 3 mm System of Measurement Metric Minimum Thickness 3 mm Color Brown Maximum Temperature 500 Degrees F Minimum Temperature -50 Degrees F Pack Size Small Pack Rockwell Hardness D87.5 Thickness Tolerance +/-0.5mm Package Quantity 10