The OneK Defender Air riding hats boast PAS015 certified to ASTM standards. They are the most adjustable around due to our revolutionary air pump system which provides ultimate comfort and a bespoke fit. The 3 air pockets at the back of the liner are inflated by pressing its concealed air pump until you get the fit you want. The quick dry liner is moisture wicking and this is helped by the multiple air vents. With enough features to appeal to those seeking everything a helmet could possibly offe