Cotton ONE HUNDRED PERCENT COTTON 300 THREAD COUNT: luxuriously soft top layer  ETERNALOFT HYPOALLERGENIC FILL: lasting support night after night  PERFECT GRIP SIDEWALLS: stretches accommodate twin and full mattresses up to 15 inches deep and queen and king mattresses up to 17 inches deep EASY CARE INSTRUCTIONS: Machine wash warm, with nonchlorine bleach when needed. Tumble dry on lowest setting separately to avoid protector damage. Dryer temps vary by brand, use the lowest setting and remove when dry. Do not iron. TEN YEAR WARRANTY: rest easy knowing you’ve made the quality, trusted choice in Sealy