A camper shell (also canopy, and sometimes topper, cap, bed cap, box cap, or simply shell) is a small housing or rigid canopy used as a pickup truck or coupe utility accessory. The housing is usually made of fiberglass or aluminum, but sometimes wood, and is mounted atop the pickup truck's rear bed. It usually covers the entire bed of the pickup truck, and is large enough to be used for camping purposes. Even though use for camping may have been its initial purpose, it now seems most often to be used for utility and storage purposes - particularly the protection of cargo from the elements and theft. Some camper shells are so large that they can overlap the top of the truck's cab, and some called soft-tops are made of canvas like convertibles.