The USAlert WatchDog LT Pager Back Cover is a durable piece of black polycarbonate material that makes up the back side of the WatchDog LT housing. Back Covers are replaceable, so pagers need not be returned for repair. When assembling the WatchDog LT housing, the Back Cover slides into place from the bottom of the pager and is held in place with a metal screw. Two other parts of the housing attach to the Back Cover, the WatchDog LT Battery Cover and the WatchDog LT Belt Clip. These two parts are also replaceable.