For my rings: Letter = Inner Diameter Number = Wire Gauge
B21
B20
B19
C21
C20
D21
D20
D19
D18
D17
E21
E20
E19
E18
E16
F20
F19
F18
F17
F16
G19
G18
G17
G16
H20
H19
H18
H17
H16
H14
I19
I18
I16
I15
J19
J17
J16
J14
K18
K17
K15
L18
L17
L16
N16
O14
P16
S14