Four-way stretch design fits all open-faced helmets, closed-faced helmets and goggles. Filter traps 99.9% of dust particles. Heat, CO² and water vapor exit mask through pair of one-way exhaust valves; helps reduce fogging. Moisture-wicking material is breathable for additional comfort. Adjustable, Padded nose bridge. Standard sizes accommodates necks up to 18”, while the XL accommodates larger necks up to 23”.