Medium-weight cotton jersey knit (200 g/sq.m), a material that is rather different from the thin stuff used with ordinary T-shirts.It has a double neckband with a 15 % lycra mix for added elasticity. Double seams at bottom and sleeve hems. The back neckline seam is covered by an extra piece of jersey material that runs down to below the shoulder seams to prevent bagginess. Size M corresponds to back length 70 cm.