Description Fast-paced lunch ride or weekend 60-miler, the Smith Persist MIPS road helmet is down for whatever you’ve got in mind. Designed to feel like it’s tailor-made for your head, you can fine tune the fit on the fly with an easy to use dial adjuster. When you’re sweating it out on the climb, 21 fixed vents and our AirEvac ventilation system keep the air flowing, your head cool and your glasses from fogging. Energy absorbing zonal KOROYD® complements Mips® Brain Protection System to reduce impact forces in the event of a crash and for the confidence to tuck every descent. Protection Lightweight in-mold construction, Zonal KOROYD® coverage for lightweight, energy-absorbing and ventilated impact protection Mips® Brain Protection System reduces rotational forces caused by angled impacts to the head Complies with U.S. CPSC Safety Standard for Bicycle Helmets for Persons Age 5 and Older as well as CE EN 1078 Fit / Integration Adjustable dial fit system for a customized fit Designed for ultimate integration with Smith performance eyewear for maximum comfort, venting and storage convenience AirEvac ventilation system integrates with Smith eyewear for fog-free lenses Size Small: 51-55cm Size Medium: 55-59cm Size Large: 59-62cm Size Extra Large: 61-65cm Features 21 fixed vents for consistent airflow Performance comfort lining Lightweight, low-bulk single layer webbing Weight (Size Medium): 300 g