6.3 oz., 100% ring spun USA cotton; Sport Grey is 90% cotton, 10% polyester; Dark Heather is 50% cotton, 50% polyester; Made with sustainably and fairly grown USA cotton; Welt-knit collar and cuffs; Three-button placket with woodtone buttons; Double-needle stitching throughout; 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