I wear this shirt periodically Periodic Table Chemistry geek 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 Features colorful periodic table with the words I wear this shirt PERIODICALLY. Awesome t shirt for Scientists and Chemistry majors and Chemists Classic funny shirt for science geeks. High quality printing Lightweight, Classic fit, Double-needle sleeve and bottom hem