6.1 oz., 100% preshrunk cotton. Seamless collar. Double-needle stitched. Taped shoulder-to-shoulder. (Ash is 99/1 cotton/poly; Sport Grey is 90/10 cotton/poly; Dark Heather, Heather Cardinal, Heather Cinnamon, Heather Forest, Heather Indigo, Heather Navy are 50/50 cotton/poly) new safety green and safety orange are 50% cotton, 50% polyester