Element of Stealth (Ni-Nj-A) T-Shirt Periodic Table 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 Ninja Periodic Table T-shirt Lightweight, Classic fit, Double-needle sleeve and bottom hem