Warm enough to wear alone, thin enough to layer. The Thermax Headliner provides cozy warmth in a lightweight and comfortable piece. Thermax is a high performance hollow core polyester that provides maximum wicking while retaining heat. With 4-way stretch, flat-seam construction, and the ability to fit seamlessly under hats and helmets this is the perfect addition to your kit. Recommended for: On-mountain cold weather adventures (skiing, snowboarding, hiking, fishing, etc) | Seirus Thermax Headliner in Black