Inside Diameter Sizes MM Inches AU, NZ, UK, IR US, CA, MX EU 11.95 0.474 A 1/2 - 12.18 0.482 A 1/2 3/4 - 12.37 0.487 B 1 - 12.60 0.496 B 1/2 1 1/4 - 12.78 0.503 C 1 1/2 - 13.00 0.512 C 1/2 1 3/4 - 13.21 0.520 D 2 41 1/2 13.41 0.528 D 1/2 2 1/4 - 13.61 0.536 E 2 1/2 42 3/4 13.83 0.544 E 1/2 2 3/4 - 14.05 0.553 F 3 44 14.15 0.557 F 1/2 3 1/8 - 14.25 0.561 F 3/4 3 1/4 - 14.36 0.565 G 3 3/8 45 1/4 14.45 0.569 G 1/4 3 1/2 - 14.56 0.573 G 1/2 3 5/8 - 14.65 0.577 H 3 3/4 46 1/2 14.86 0.585 H 1/2 4 - 15.04 0.592 I 4 1/4 47 3/4 15.27 0.601 I 1/2 4 1/2 - 15.40 0.606 J 4 5/8 49 15.53 0.611 J 1/4 4 3/4 - 15.70 0.618 J 1/2 5 - 15.80 0.622 K 5 1/8 50 15.90 0.626 K 1/4 5 1/4 - 16.00 0.630 K 1/2 5 3/8 - 16.10 0.634 L 5 1/2 51 3/4 16.30 0.642 L 1/4 5 3/4 - 16.41 0.646 L 1/2 5 7/8 - 16.51 0.650 M 6 52 3/4 16.71 0.658 M 1/2 6 1/4 - 16.92 0.666 N 6 1/2 54 17.13 0.674 N 1/2 6 3/4 - 17.35 0.683 O 7 55 1/4 17.45 0.687 O 1/2 7 1/4 - 17.75 0.699 P 7 1/2 56 1/2 17.97 0.707 P 1/2 7 3/4 - 18.19 0.716 Q 8 57 3/4 18.35 0.722 Q 1/2 8 1/4 - 18.53 0.729 Q 3/4 8 1/2 - 18.61 0.733 R 8 5/8 59 18.69 0.736 R 1/4 8 3/4 - 18.80 0.740 R 1/2 8 7/8 - 18.89 0.748 R 3/4 9 - 19.10 0.752 S 9 1/8 60 1/4 19.22 0.757 S 1/4 9 1/4 - 19.31 0.760 S 1/2 9 3/8 - 19.41 0.764 S 3/4 9 1/2 - 19.51 0.768 T 9 5/8 61 1/2 19.62 0.772 T 1/4 9 3/4 - 19.84 0.781 T 1/2 10 - 20.02 0.788 U 10 1/4 62 3/4 20.20 0.797 U 1/2 10 1/2 - 20.32 0.800 V 10 5/8 63 20.44 0.805 V 1/4 10 3/4 - 20.68 0.814 V 1/2 11 - 20.76 0.817 W 11 1/8 65 20.85 0.821 W 1/4 11 1/4 - 20.94 0.824 W 1/2 11 3/8 - 21.08 0.830 W 3/4 11 1/2 - 21.18 0.834 X 11 5/8 66 1/4 21.24 0.836 X 1/4 11 3/4 - 21.30 0.839 X 1/2 11 7/8 - 21.49 0.846 Y 12 67 1/2 21.69 0.854 Y 1/2 12 1/4 - 21.89 0.862 Z 12 1/2 68 3/4 22.10 0.870 Z +1/2 12 3/4 - 22.33 0.879 Z+1 13 - 22.60 0.890 Z+1.5 13.5 - 22.69 0.893 Z+2 - - 22.92 0.902 Z+2.5 - - 23.06 0.908 Z+3 - - 23.24 0.915 Z+3.5 - - 23.47 0.924 Z+4 - - 23.55 0.927 Z+4.5 - - 23.87 0.940 Z+5 - - 24.27 0.956 Z+6 - - Visit the Creidne Jewelry - Exquisite Silver Jewelry main page.