The 525 Thread Count Sheet Set is made of 100% soft long staple cotton. The finish weave is made of single ply yarn to give you a smooth, silk, luxurious finish. The sheets are over-sized to ensure your comfort - the fitted sheet will fit up to a 20" mattress and will always stay in place with fully elastic around the whole sheet. We offer many sizes and colors to coordinate with any decor you may have. Over-sized pillow cases for your comfort.