S1 Lifer RAD Helmet Sizing Liner

Rad Liner (solo photo)

S1 RAD Liners are an impact reducing sizing liner that Reduce, Absorb, and Disperse impact energy away from the head when impacted.


  • RAD liners serve a dual purpose by both acting as your helmets sizing liner while also adding an extra layer of impact reducing foam to your helmet. Lab tests show that depending on the impact RAD Liners reduced impact energy an additional 7.5% to 16.5% averaging a 12% energy reduction to the head in all liners tested.


RAD Liners are sized just like S1 standard sizing liners and fit into all S1 Lifer Helmets and are covered in a sweat absorbing, hand-washable terry cloth fabric.

Fits head sizes: "21 - 23.5"
S 21"
M 21.5"
L 22"
XL 22.5"


S1 RAD Liners reduce the risk of head injury, compared to no head protection. Leading medical doctors, PhD’s and scientists have concluded that a reduction in impact energy to the head correlates with a reduction in concussion risk. You can still sustain a head injury even with head protection, and no helmet or impact reducing sizing liner can prevent concussions or eliminate the risk of these types of injuries.


If you are adding these terry liners into a helmet that you have already worn please wash the contact points wear you plan to place the new velcro with a wet cloth to wipe away any sweat residue that may have built up on the surface of the inner helmet shell. Doing this will ensure that the Velcro will stick firmly to the inner shell.