SIZE CHART

DIAMETER MM	US/CANADA	UK/AUSTRALIA
15.7 mm	5	J 1/2
15.9 mm	5.25	K
16.1 mm	5.5	K 1/2
16.3 mm	5.75	L
16.5 mm	6	L 1/2
16.7 mm	6.25	M
16.9 mm	6.5	M 1/2
17.1 mm	6.75	N
17.3 mm	7	N 1/2
17.5 mm	7.25	O
17.7 mm	7.5	O 1/2
17.9 mm	7.75	P
18.1 mm	8	P 1/2
18.3 mm	8 1/4	Q
18.5 mm	8 1/2	Q 1/2
18.7 mm	8 3/4	R
18.9 mm	9	R 1/2
19.2 mm	9.25	S
19.4 mm	9.5	S 1/2
19.6 mm	9.75	T
19.8 mm	10	T 1/2
20 mm	10.25	U
20.2 mm	10.5	U 1/2
20.4 mm	10.75	V
20.6 mm	11	V 1/2
20.8 mm	11.25	W
21 mm	11.5	W 1/2
21.2 mm	11.75	X
21.4 mm	12	X 1/2
21.6 mm	12.25	Y
21.8 mm	12.5	Z
22 mm	12.75	Z 1/2
22.2 mm	13