Solid colors are made of 100% Cotton. Heather Grey consists of 90% Cotton and 10% Polyester. Dark Heather and Heather Blue contain 50% Cotton and 50% Polyester. Dark Heather, Heather Blue, and all other heathers are composed of 65% Polyester and 35% Cotton. Girls' Heathers are made of 60% Cotton and 40% Polyester.