Tonneau cover (US /tʌˈnoʊ/ or UK /ˈtɒnoʊ/) describes a hard or soft cover used to protect unoccupied passenger seats in a convertible or roadster, or the cargo bed in a pickup truck. Hard tonneau covers open by a hinging or folding mechanism while soft covers open by rolling up.The tonneau cover is used to conceal and or cover cargo. When the cover is pulled out, it keeps items out of the sun and provides extra security by keeping personal items out of sight.