9 Pc Red 8Mm Billet Aluminum Cup Washer Kit For Honda/Acura Header Bolts 8 Mm Cup washers have a diameter of 19mm, depth is 8.4mm. Set includes nine washers and bolts as seen in picture 8mm Bolts with 24.45mm long threading, and 8x1.25 thread pitch. Add that final touch to your car with this high quality part. Perfect to replace header bolts.