Wear it for your warm-up, or just to warm up. The Glacier Half-Zip offers great warmth for its weight with a 6.3-oz. fleece lined 94% polyester, 6% spandex knit. Full underarm gussets allow easy movement. Front zipper allows you to moderate your body heat. A zippered chest pocket offers within-reach storage when worn as a base or middle layer. Imported. Material: Fleece, Polyester, Spandex.