Give credit where credit's due. Thank your mom, your legs, and your gear for giving you the opportunity to land that rocky gap. Made for going big, going fast, or both, the Smith Mainline is our pinnacle, downhill certified enduro bike helmet. Safety innovations like Koroyda and MIPS provide energy-absorbing impact protection so you have the confidence to get aggressive on the trail. It doesn't matter if you're slaying the EWS in Whistler or suffering through the last stage of your local enduro race, you need a breathable, lightweight helmet that pairs well with goggles and fits like a glove. The Mainline integrates with your bike goggles for efficient venting and fog-free vision. Multiple pad sets including liners and neck-rolls let you customize the fit. Protection Complete Koroyd® coverage for lightweight, energy-absorbing and ventilated impact protection MIPS® Brain Protection System reduces rotational forces caused by angled impacts to the head CPSC, CE EN1078 and ASTM F1952 (Downhill) certified Fit / Integration Designed for ultimate integration with Smith MTB goggles for maximum comfort, fit, and venting AirEvac™ ventilation system integrates with Smith goggles for fog-free lenses Three washable cheek pad kits, two crown liners and two neck rolls let you fine tune the fit D-ring chin strap fastener for a snug fit Features 21 fixed vents for consistent airflow Adjustable visor Hybrid X-STATIC® / XT2® anti-bacterial performance lining for odor resistance Weight (Size M, MIPS®): 27 oz / 770 g Size Head Circumference S 51-55cm M 55-59cm L 59-62cm SMITH 1965 Smith is born In 1965 Dr. Bob Smith, orthodontist and original ski bum, develops the first sealed thermal lens and breathable vent foam. He hand builds goggles in his garage and sells them out of his van on weekend ski trips in Utah and Colorado.