Flat Washer Flat Washer Type Standard Dimensional Standards ANSI B18.22.1 Material PEEK Material Grade/Class Grade 2 Finish Plain For Screw Size M3 Inside Diameter 3.9 mm Outside Diameter 9 1/2 mm Maximum Thickness 1.1 mm System of Measurement Metric Minimum Thickness 1.1 mm Color Natural Maximum Temperature 500 Degrees F Minimum Temperature -50 Degrees F Pack Size Small Pack Resistance Properties Impact Resistant Radiation Resistant Wear Resistant Rockwell Hardness M103