Solid Navy 550 Thread Count Cal king Waterbed Sheet set 100% Cotton 4pc Sheet set deep pocket unattached 550TC 100% Cotton Experience true luxury when you sleep on these woven solid cotton sheets 550 thread count. Cotton King/ Cal king unattached water bed sheet set with fitted, Flat & Pillow cases 550 thread count.Thread count is the number of threads per square inch of fabric--the higher the thread count, the thicker, more durable and longer lasting the material Fitted sheets will fit mattress up to 18 inches deep ,Elastic all around for a perfect fit Machine wash.Softness enhansed with each washing