The cargo bed enclosure does exactly what it states: It covers the cargo bed area, and it does this with a sliding lockable top. Sometimes people call it a roll-top. It's a great way to keep things out of sight and safe from much of the environment too. These tops come in two and three-piece units. The two piece unit opens up approximately half of the bed area, and the three-piece opens up about two-thirds of the bed area. The standard height, is at the top of the side lids, and then there are two other heights, one is cab-high, and the other is taller, often about 39" above the service body lids. Depending on what you intend to carry inside that bed area, this will determine the best cargo bed enclosure for your needs. If you have any questions, give the Paradise Chevrolet Fleet team a call at 951-252-2980, and you can also find a lot of information about truck bodies and truck body options and accessories on our Fleet website at http://www.paradiseworktrucks.com.