Not sure about your helmet size? Get an “S1 Helmet Co. Fit All Kit” and eliminate any guessing.
You’ll get all 6 different thickness of sizing liners so you can fit your helmet perfectly now or if your head grows .
Size: Small- XXX Large included in fit kit.
FIT ALL KIT SIZES
(S1 Mini Lifer Helmets 19″ – 20.5″)
(S1 Lifer Helmets 21″ – 23.5″)
(S1 Mega Lifer Helmet 24″ – 25.5″)