The Chill-Its 6630 Skull Cap is a low-profile cap featuring a wide, absorbent terry cloth sweatband to manage perspiration away from your eyes, face and glasses. The Hi Cool moisture management performance fabric is stretchy enough to fit most heads and can be worn under a hard hat or on its own to provide sun-blocking protection. The low-profile design fits comfortably under a hard hat or helmet and is great for construction workers, landscaping, roofing, or anybody working in the heat. Can also be used to reduce the risk of heat stress while mountain biking, motorcycling, gardening, hiking, playing sports and more.