Perfect Fit Density Pillow 4-Pack - Extra Firm King Every Wellrest density pillow shell is constructed out of 233 thread count cotton sateen and is filled with 100% Slumbersoft polyester fill A gusseted custom color quilted sidewall and reinforced corded edges were engineered into the pillow to provide extra support The green medium density is designed for stomach sleepers, blue firm density for back sleepers, and purple extra firm density for side sleepers This pillow is also machine washable King size measures 20" x 36"