A waterproof, windproof, breathable Weather Shield membrane is laminated between the nylon outer shell and insulating lining for warmth * Nylon outer face is tough yet flexible to allow complete comfort; fleece inner face is soft and warm against your skin * Wear three ways: as a neck gaiter only, as a face shield/neck gaiter or as a full hood * To determine size, measure circumference of head just below your nose. Size S/M fits 20 - 24 inches and size L/XL fits 22 - 26 inches.