■ Genuine Tortoise Shell Ring - 31 (No. 15, No. 5) ★ Front Height 0.8 inch (20 mm) Width 0.6 inch (16 mm) Thickness 0.2 inch (6 mm) ★ Back Side 0.2 inch (5 mm) ★ Stock No. 15,5 ◎ Please choose the size up your K18 size. Comes with a tortoise shell warranty.