SRI Performance RYR-020 : Rocker Arm Shim, Block Style, Ford D3, 0.020" Thick

Racing Helmets

helmet	size	measurement	metric
XS	6-5/8 to 6-3/4	20-7/8 to 21-1/4	53 to 54
S	6-7/8 to 7	21-5/8 to 22	55 to 56
M	7-1/8 to 7-1/4	22-3/8 to 22-3/4	57 to 58
L	7-3/8 to 7-1/2	23-1/8 to 23-1/2	59 to 60
XL	7-5/8 to 7-3/4	23-7/8 to 24-1/4	61 to 62
2XL	7-7/8 to 8	24-3/4 to 25-1/8	63 to 64

CMR Helmets

helmet	size	measurement	metric
XS	6-1/2 to 6-5/8	20-1/2 to 20-7/8	52 to 53
S	6-3/4 to 6-7/8	21-1/4 to 21-5/8	54 to 55
M	6-7/8 to 7	21-5/8 to 22	55 to 56
L	7-1/8 to 7-1/4	22-3/8 to 23-3/4	57 to 58

Rookie Helmets

helmet	size	measurement	metric
One size	6-3/4 to 7	21-1/4 to 22	54 to 56