Periodic Table T Shirt Color Coded 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 Classic Color Periodic Table of Elements T-Shirt Dmitri Mendeleev Chemistry Periodic Table Tee Lightweight, Classic fit, Double-needle sleeve and bottom hem