SPECS: Small: 51-55 cm Medium: 55-59 cm Large: 59-61 cm DESIGN & TECHNOLOGY: Hybrid construction offers lightweight comfort of an in-molded shell blended with high exterior durability 21 vents promote air movement using fine-tunable airflow and easy one-handed dual adjustability Anti-fog proven goggle clearing Smith AirEvac (TM) tech Head customizable micro-adjustment of size around full circumference of skull with BOA ® 360 Fit System Sweat-activated odor control with XT2 (R) anti-microbial lining Removable SnapFit SL2 ear pads allow easy reset back into place Audio chip compatible ear design Compatible with Outdoor Tech (TM) audio system Designed for ultimate integration with Smith goggles for maximum comfort and venting SAFETY FEATURES: Zonal Koroyd (TM) coverage offers lightweight energy-absorbing impact protection for minimal force to the head MIPS (R) Advanced Brain Protection System reduces rotational forces caused by angled impacts ASTM F 2040, CE EN 1077:2007 Class B, CPSC, CE EN1078 Certified