Lock Washer Lock Washer Type Wedge Lock Finish Delta Protect Material Steel For Screw Size 12 mm Inside Diameter 12.95 mm Outside Diameter 23.8 mm Maximum Thickness 4.22 mm Assembly Thickness 4.22 mm Color Silver Material Grade/Class Case Hardened Pack Size Small Pack Resistance Properties Shock Resistant Vibration Resistant Rockwell Hardness HRC40 System of Measurement Metric Package Quantity 100