3mm, Smallest Domed Cap Outside Diameter: 10mm.8mm, Cup Inside Diameter Largest Size: 11.7mm, Cup Hole Diameter Largest Size: 5.5mm, Largest Domed Cap Outside Diameter: 16.
RS PRO 2 piece Nylon 66 Domed Cap & Cup Washer Kit, For Thread Size: M6, Finish: Bright Zinc Plated, Domed Cap Height Largest Size: 4mm, Cup Hole Diameter Largest Size: 6.