Usually made of wool (but not the thick, scratchy type found in winter sweaters), polyurethane laminate fabric or fleece, a diaper cover is a separate, waterproof layer that goes on top of a cloth diaper. It prevents leaks and protects your baby's clothes from moisture. In addition to varying in levels of absorbency, diaper covers run the gamut in style, from basic to fancy: Some are pull-ups, while others fasten with snaps or Velcro tabs, and they come in lots of colors and patterns. When the weather is warm enough, many parents let their babies bum around in diaper covers; this also makes for quicker changing. You'll probably want to have five or six. They can be reused two or three times before they need to be thoroughly cleaned; just wipe the inside with a damp cloth. Prices start at about USD 8 and top out at USD18 or so.