Material: Stainless Steel, Laser Engraving No Rust, No Fading Ring size 7 diameter 17.3 mm （0.68 inch）perimeter 54.4 mm 8 diameter 18.1 mm（0.71 inch） perimeter 57 mm 9 diameter 18.9 mm （0.74 inch）perimeter 59.5 mm 10 diameter 19.8 mm（0.78 inch）perimeter 62.1 mm 11 diameter 20.6 mm （0.81 inch）perimeter 64.6 mm 12 diameter 21.4 mm （0.84 inch）perimeter 67.2 mm 13 diameter 22.3 mm （0.88 inch）perimeter 70 mm