RING DIAMETER (MM)

USA/CANADA

14.0mm	3
14.4mm	3.5
14.8mm	4
15.2mm	4.5
15.6mm	5
16.0mm	5.5
16.5mm	6
16.9mm	6.5
17.3mm	7
17.7mm	7.5
18.2mm	8
18.6mm	8.5
19.0mm	9
19.4mm	9.5
19.8mm	10
20.2mm	10.5
20.6mm	11
21.0mm	11.5
21.4mm	12
21.8mm	12.5
22.2mm	13
22.6mm	13.5