S1 Helmet Company : Sizing Instructions

Measure the circumference of your head and then figure out what size helmet you are. 

S1 Mini Lifer Helmet fits 18.5" - 20.5"

S1 Lifer Helmet fits 20.5" - 23.5"

S1 Lifer Helmet w Visor fits 20.5" - 23.5"

S1 Retro Lifer Helmet fits 20.5" - 23.5"

S1 Lifer w Brim Helmet fits 20.5" - 23.5"

S1 Retro Lifer E-Bike Helme fits 20.5" - 23.5"

S1 Mega Lifer Helmet fits 23.5" - 25.5"

* and don't worry about exact sizing because you can use the replaceable color coded sizing liners to get a comfy and perfect fit!