These are Happy Heinys specially manufactured Micro-Fiber Terry inserts. They have been manufactured for Happy Heinys and are chemical free. They are made of 3 layers of soft and very absorbant micro-fiber. They are contoured to fit perfectly in a happy heiny pocket diaper. Choose from x small, small or large. X small are made for X small diapers (tiny heiny's). Smalls fit in small diapers and large fit into medium - Xlarge diapers.