Details Long winding descents and race-day lead-outs, the Smith Trace bicycle helmet is all about versatility. Road, gravel or bikepacking, this bike helmet pairs complete Koroyd® with MIPS® for protection you can trust if the route gets hairy. And when the day heats up, you'll stay cool thanks to internal air channels with intake and exhaust ports that keep the air flowing. Side channels let you securely stash your sunglasses when you don't need them, and when you do, Smith's AirEvac™ ventilation system prevents them from fogging up. Construction Complete Koroyd® coverage for lightweight, energy-absorbing and ventilated impact protection In the event of an impact, Koroyd's welded tubes collapse instantly and evenly, absorbing maximum force in a controlled manner and thus reducing the amount of energy transferred to the head. The air circulates evenly through the open cells, while the warm air in your head can easily escape, ensuring more efficient cooling under the most intense conditions. Characterized by tubes with the thinnest walls in the world, the Koroyd structure is composed of 95% air. This reduces weight and improves comfort without compromising safety. MIPS® Brain Protection System Found inside the helmet, generally between the comfort padding and the EPS (a high-quality foam used to reduce energy), MIPS® (Multi-directional Impact Protection System) BPS reduces rotational forces caused by angled impacts to the head. For certain impacts, the MIPS® BPS can reduce harmful forces transmitted to the brain. Integrated skeletal structure creates a roll cage for added strength and impact protection CPSC and CE EN 1078 certified Fit VaporFit™ dial adjustment system offers 270-degree fit adjustment with the turn of a dial Ventilation 18 fixed vents for consistent airflow AirEvac™ ventilation system integrates with Smith eyewear for fog-free lenses Details Ionic+® antimicrobial lining offers sweat-activated odor control Designed for ultimate integration with Smith performance eyewear for maximum comfort, venting and storage convenience Lightweight, low-bulk single layer webbing Helmet Size XS48-52cm S51-55cm M55-59cm L59-62cm XL61-65cm Weight (Size M, MIPS®): 10 oz / 280 g Smith Trace MIPS Bicycle Helmet