TechNiche Heat Pax Air Activated Heating Winter Liner is designed for use with hard hats (not included) to keep your head and neck warm during the cold, winter season to prevent them from freezing. It is made of 100% poly-fleece which provides warmth and protection to your head, plus it is soft and durable enough to provide both comfort and durability. It also has a black cotton-poly elastic trim for a more snug fit, hard hat fastening, and hook and loop lock to keep it more secured. It has a built-in Heat Pax Mini Warmer Pocket over the ears and includes one pair of air-activated Heat Pax Mini Hand Warmers which delivers up to 8 hours of heat. Available in black and adult size that fits all.