Copper Washer - Small A simple round copper sealing washer, 10 x 6.4 x 2mm. Copper washers deform slightly under torque to create a reliable seal on fittings and banjo bolts - inexpensive insurance against weeping leaks. SPECIFICATIONS Outer diameter: 10mm Inner diameter: 6.4mm Thickness: 2mm COMPATIBILITY Fits: general-purpose fitting and banjo bolt applications requiring a 6.4mm bore sealing washer INSTALLATION DIY-simple - drop it under the fitting and torque as normal. PRO TIPS Copper washers work best once - if you're re-torquing a fitting you've already disassembled, replace the washer rather than reusing it, since copper work-hardens and won't reseal as reliably the second time.