The Rump•a•rooz® Onesize Cloth Diaper has 4 sizes which are adjustable by the rise snaps on the front of the diaper. The Rump•a•rooz® is the first onesize diaper that starts fitting at 6 lbs, no more waiting for your newborn to put on a few pounds before wearing cloth diapers! Available in both Snap and Aplix (Velcro) closure, the Rump•a•rooz® are a pocket diaper system. Each diaper comes with a "6•r soaker" which has 6 absorbency and size setting to best customize the fit and function of the Rumparooz for your child. The 6•r soaker is inserted in the pocket opening on the inside of the Rump•a•rooz® to make the diaper absorbent. The Rump•a•rooz® diaper itself is made of a PUL (1000 thread count polyester interlock knit with a urethane laminate) which is waterproof. The inside of the diaper, which lies against baby's skin, is a scrumptiously soft microchamois which is 100% hpo-allergenic and no-pill.