6.1 oz., 100% preshrunk cotton. Seamless collar. Double-Needle Stitched. Taped shoulder-to-shoulder. Ash is 99% cotton, 1% polyester; Sport Grey is 90% cotton, 10% polyester; Dark Heather, Heather Cardinal, Heather Cinnamon, Heather Forest, Heather Indigo, Heather Navy, Safety Green and Safety Orange are 50% cotton, 50% polyester.