Helmet Smith Mainline MIPS - Matte ChalkHelmet Smith Mainline MIPS Matte Chalk The pinnacle helmet in Smith's mountain bike collection is the all new, DH certified, Mainline. Featuring complete Koroyd coverage and the MIPS rotational system, the Mainline provides exceptional protection while combining internal air channels and open exhaust ports to maximize breathability. As goggle fit and ventilation are crucial for grueling days, the AirEvac system relieves hot air that builds up on your