A bag-in-box or BIB is a container for the storage and delivery of liquids and syrups. It consists of a strong bladder (or plastic bag), usually made of several layers of film or other plastics, seated inside a corrugated cardboard box. BIBs are used used to package wine, soda fountain syrup products, milk, condiments such as ketchup or mustard, liquid chemicals, and even water. For commercial syrup applications, the customer opens one end of the box (sometimes via a pre-scored opening) and connects a compatible connector to a fitting on the bag to pump out its contents. The fitting itself contains a one-way valve which opens only with pressure from the attached connector and which prevents contamination of the syrup in the bag.