The Windham uses Anon\'s endura hard shell construction along with revolutionary WaveCel technology to create a helmet that\'s tough and durable while offering top-end safety. The liner is made from an impact-absorbing ePS foam with an integrated Wavecel layer, a collapsible cellular structure of interconnected shock absorbers that can flex, crumple and glide in the event of an accident; this process allows it to absorb energy and divert rotational forces away from the head. Passive ventilation channels enable air to flow through the helmet for temperature control, while the Polartec Power Grid fleece lining and ear pads wick moisture and dry quickly for added comfort. A dial on the rear of the helmet controls the 360° BOA fit system which wraps around the head, simply twist for micro-adjustment. The magnetic Fidlock chin buckle can be opened/closed using one hand, even with gloves on, and the tool-free removable clip at the back helps keep your goggles securely in place. The helmet is also compatible with Outdoor Tech aftermarket headphones. Size GuideSmallMediumLarge52-55cm56-59cm60-62cmClick here for more information on our Size & Fit GuideVenting: Passive Sizing System: AdjustableWeight: 654gConstruction: Hard ShellSafety standard: eN 1077 Class B, ASTM F 2040Additional SafetyWaveCel technology behaves like a network of hundreds of interconnected shock absorbers that sit between your head and the outer shell of the helmet. It helps distribute the energy from an impact, reducing forces like a crumple zone of a car and then helping to divert rotational forces by flexing and gliding. VentingPassive ventilation channels built into the helmets shell and liner draws fresh air in through the front and pulls moist air out the back.Sizing SystemThe fully integrated 360° BOA Fit System wraps completely around the wearers head allowing for micro-adjustment by simply twisting the dial at the rear. Constructionendura shell construction features an injection-moulded ABS exterior for long-lasting durability and ding-resistant strength. Built for season after season of knock-around wear and tear.