INSIDE DIAMETER
CONVERSION CHART
INCHES
MM
UK
US
EUROPE
0.52
12.84
D
2.25
41
0.53
13.57
E
2.75
42
0.55
13.97
F
3.25
44
0.56
14.38
G
3.75
45
0.58
14.88
H
4.25
46.5
0.59
15.10
I
4.5
47
0.60
15.49
J
5
48.5
0.62
15.90
K
5.5
50
0.64
16.31
L
6
51
0.65
16.71
M
6.5
52
0.67
17.12
N
6.75
53.5
0.69
17.53
O
7
55
0.70
17.93
P
7.5
56
0.72
18.34
Q
8
57
0.73
18.75
R
8.5
58.5
0.75
19.15
S
9
59.5
0.77
19.56
T
9.5
61
0.78
19.81
U
10
62.5
0.79
20.17
V
10.5
63
0.81
20.61
W
11
65
0.83
20.99
X
11.5
66
0.84
21.32
Y
12
67.5
0.85
21.71
Z
12.5
69
0.87
22.10
Z+1
13
70.5