Smith Bike Helmets Mainline Mips Helmet AC / Iago Garay Large E007423585962. 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 Koroyd 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.