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 Tardigrades are awesome! This is the perfect shirt for scientists, cell biologists, school teachers molecular biologists, doctors, physicians, pharmacists, bacteriologists, microbiologists, and chemist majors. Wear it during lab tests, chemical reactions vials, class experiments, around atoms, or funny science charts. When life gives you mold, make penicillin! Perfect for your nerdy son or daughter heading to college for their undergrad degree. Lightweight, Classic fit, Double-needle sleeve and bottom hem