Our certified Pima cotton is extra-long staple cotton, known for its long, smooth fibers. It is woven into a high quality fabric that is soft and durable. With a thread count of 400 per square inch, we have also created a sheet that is breathable. The threads are not overly compacted, as with extra high thread count sheets, thereby allowing the air to flow through the sheet and keep you cool. 400 thread count, certified pima cotton, sateen weave Hidden 60” zipper on the side for easy removal and cleaning Machine Washable 4 corner tie-downs match with our duvet's corner loops to keep everything in place Includes a set of pillowcases (1 for twin size) Oversized to account for shrinkage Housewife fold on pillowcases prevent pillow slippage and help to dress the bed