A3 Helmet W/MIPS 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 safety, ventilation that will you keep you cool on the longest climbs with comfort and coverage to protect on the sketchiest of descents. Highest possible score (5-STAR) from Virginia Tech helmet safety lab so you can feel confident in all conditions. This helmet is designed and intended exclusively for use by bicycling activities, including mountain biking and off-road cycling.