Cellophane on the back of an adhesive shell Some types of packaging are examples of oyster shells. This type of plastic has a transparent side and a clamshell side, which is called clamshell back. This type of packaging is used when the seller wants to provide the possibility to see the contents inside the package. Cable packaging, CD/DVD covers and small electronic parts are of this type. These films are made of BOPP, which can be laminated. For this purpose, a layer of CPP film is usually laminated on the desired surface to increase strength and sewability.