Diaper covers are required for use with some cloth diapers, usually diapers called fitted cloth diapers or prefolds. The fitted diaper or prefold absorbs wetness and the cover keeps the wetness from going through to your baby's clothes. Put the fitted or prefold onto your baby first and then put the cover over top, making sure that all of the diaper is tucked inside the cover.
Generally you will need one diaper cover for every 3 - 6 diaper you have. The diaper will get washed with every use but the cover can last a few changes. If just the inside of the diaper gets wet and the cover stays dry, the cover can be reused. If the cover is damp you can give it a wipe or a rinse and then air dry or if it's a wool cover it can simply air dry between uses and then be washed as required.
A frugalista favourite. The SUPER LITE can be combined with any absorbent insert or fitted diaper to create an effective and economical 2-piece diaper.