USAF Officer Training School 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 United States Air Force Lightweight, Classic fit, TearAway label, Double-needle sleeve and bottom hem Officer Training School 4.5 oz 100% Combed Ringspun Cotton, machine wash cold with like colors, dry low heat