Actually I am a rocket scientist Tee 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 This a funny saying for the smart alec in the family, especially if they happen to be an aerospace engineer. Great gift idea for any clever smarty pants you know. Lightweight, Classic fit, Double-needle sleeve and bottom hem