Definitely works for the extra thick mattresses. Cotton blend material that is smooth with no pattern. Typical of what retailers are selling featuring the wrinkle free cotton blend materials. I am pleased with everything except the price, hence the 1 star deduction. Ive consistently purchased similar quality sheets for less than the sale price. However, the sheets are acceptable. Also, Ive managed to keep the white cotton blend sheets white with bleach for colors. They wash fine.