5.4 oz., 100% preshrunk heavyweight cotton; Double-needle stitching on neck, sleeves and bottom hem and TearAway™ label; Shoulder-to-shoulder tape seamless collarette & Certified Oeko-Tex® Standard 100; Heather Dark Grey and Moss are not Oeko-Tex® certified; Heather Grey is 90% cotton, 10% polyester; www.TrackMyT.com; Heather Dark Grey, Neon Blue, Neon Green, are 50% cotton, 50% polyester; Neon Orange, Neon Pink and Neon Yellow are 50% cotton, 50% polyester ;