Trivia Crack Professor E=mc2 T-Shirt Solid colors: 100% Cotton; Heather Grey: 90% Cotton, 10% Polyester; All Other Heathers: 50% Cotton, 50% Polyester Imported Machine wash cold with like colors, dry low heat Official Trivia Crack Merchandise From the #1 mobile trivia game Lightweight, Classic fit, Double-needle sleeve and bottom hem