This is a 100% virgin wool, pull-on cover which goes over a diaper. These are extremely well-crafted soakers hand-made by a Canadian family-owned business. They are breathable since they are wool, yet soft to the touch. Wool has its own lanolin which makes them water repellent and very effective for preventing leaks. These are knit from natural untreated wool yarn. Since untreated wool inhibits bacteria growth it does not need to be washed as often unless soiled. Additionally, it won't smell of urine once dry. Hand wash and line dry. A wonderful investment that you will absolutely not regret!