Top Mount Tonneau Covers don't need a whole lot of description beyond their own name. The anodized aluminum frame that they mount on rides right on top of the truck bed and is held in place by clamps. A Flip-Lock system makes it possible to easily attach and detach the cover, and there is easy access to the tailgate. Many people who purchase the top mount cover use it to keep tools and perishables out of the sun, and away from prying eyes. It doesn't take too long to assemble the cover, but when you do you'll notice a difference soon enough. For one thing, your gas mileage may increase, depending on your driving habits and other conditions. For another, you now have a sleek, stylish cover for your truck bed. By keeping out rain and ice, you also prevent corrosion, especially if you live anywhere that salt is used to keep the roads from freezing. The salty dirt used on roads ends up in the back of your truck, and soon enough you've got rust spots from scratches and exposed metal that's been bathed in sodium chloride. You may already have an ugly truck bed, and if you do then a Lebra Top Mount Tonneau cover is the choice for you.