Flat Washers are Used to Improve Stress Distribution and to Span Large Clearance Holes; Washers are Designed for Assembly Around a Bolt or Screw, Between the Bearing Surface of the Fastener and the Part to Which it is AttachedSpecifications:Type: RoundFastener Size: 1/2 InchInner Diameter: 9/16 InchOuter Diameter: 1-3/8 InchThickness: 12 GaugeMaterial: Silicon Bronze