4.5 oz., 100% preshrunk cotton; Sport Grey is 90% cotton, 10% polyester; Seamless double-needle stitched collar; Taped neck and shoulders; Double-needle stitched sleeves and bottom hem; Sport Grey is 90% cotton, 10% polyester; 3/4" collar; Hemmed sleeve; Gildan's manufacturing process utilizes 45% renewable energy; Gildan?s Community Investment Program supports education, the environment, humanitarian aid and active living in the communities we do business in