Designed to be comfortably worn under a helmet, the 509 Midweight Balaclava features laminated windproof front panels, a laser cut eyeport and mouth vent to eliminate seams against the face, and offers midweight warmth for cold days on the hill. Breathable material in key ventilation areas helps prevent overheating while added length at the neck keeps this balaclava tucked into your base layer all day long.