So comfortable you won't ever want to take it off. The A3 mountain bike helmet is a new standard in premium mountain bike helmets with luxurious comfort, patent-pending innovations in coverage, ventilation that will you keep you cool on the longest climbs with comfort and coverage on the sketchiest of descents. B-Series MIPS creates an optimal 360-degree fit that can maximize the features built into the A3. TLD Sweat Glide System, carefully designed EVA wicking foam behind the comfort liner along the brow, directs sweat away from eyes and optics. Not intended for use with motorized vehicles.