Check the listing for details. 6D Helmets® ATR -2 Helmet Liners (choose your size). Condition: New with tags. Listed at 50.59 USD. 6D Helmets® ATR -2 Helmet Liners (choose your size) Their name 6D is a reference to the engineering term 6 Degrees of Freedom, which refers to the ability to move 3 dimensionally in space about the Cartesian coordinate system of X,Y and Z, including rotation about each axis. Their Omni-Directional Suspension system utilizes this term to maximize its ability to absorb and mitigate energy. 6D Helmets® are dedicated to the relentless pursuit of brain protection. This has become their challenge and their goal: to develop a revolutionary design concept utilizing creative, forward-thinking technology that would change the market and improve the safety capabilities of the sport’s helmet. 6D’s exclusive patented Omni Directional Suspension™ provides protection capabilities unmatched by any other helmet or helmet technology. The inner EPS liner is the first layer of defense and a very important component of the new advanced ODS design. It is effectively a helmet within a helmet. It has its own in-molded PVC (Polyvinyl Chloride) shell that serves many functions. It nests into the ODS carrier, provides strength and integrity to the EPS, and serves as a slippery surface to aid in reducing angular acceleration forces. The EPS is of a softer density than the EPP and is secured into the helmet with 4 locking pins that mate to the ODS carrier. It is also captured by the Chin Bar EPP which provides additional security.Replacement liner for 6D Helmets ATR-2 helmetsWashable Dri-Lex linerThank you for your business and may you have happy trails from here and forever! RoomaZoom Powersports