My Password Is The Last 8 Digits of Pi Funny Math Joke 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 In men's, women's, and youth sizes for your choice and comfort. This tee is perfect for a birthday, Christmas, graduation, or any gift giving occasion. Multiple color variations. Lightweight, Classic fit, Double-needle sleeve and bottom hem