GS - 40 to 65 lbs.
GM - 65 to 75 lbs.
GL - 75 to 90 lbs.
WS - 90 to 110 lbs.
WM - 110 to 130 lbs.
WL - 130 to 155 lbs.
WXL - 155 to 180 lbs.
WXXL - 180 to 220 lbs.
XS - 90 to 110 lbs.
S - 110 to 130 lbs.
M - 130 to 155 lbs.
L - 155 to 185 lbs.
XL - 185 to 225 lbs.
XXL - 225 to 275 lbs.
4L - 275 to 340 lbs.
(4L equal to XXXL custom only)
BOYS
YS - 40 to 60 lbs.
YM - 60 to 75 lbs.
YL - 75 to 90 lbs.
GIRLS
GS - 40 to 65 lbs.
GM - 65 to 75 lbs.
GL - 75 to 90 lbs.
ADULT
Over 18 inches - XXL
17 to 18 inches - XL
15.5 to 17 inches - L
13.5 to 15.5 inches - M
11.5 to 13.5 inches - S
10.5 to 11.5 inches - XS
YOUTH
10.5 to 11.5 inches - YL
9.5 to 10.5 inches - YM
8.5 to 9.5 inches - YS