BCI Fabrication Slanted Top Mount Flatbed Toolbox 48" Single Lid Model SSB4BCI Fabrication Slanted Top Mount Flatbed Toolbox Single Lid Model SSB4 BCI toolboxes feature a heavy duty 12 gauge steel construction and a Line X Polyurea coating. The SSB4 is a heavy duty top mount box that works great on a flatbed. A lot of our customers install one SSB4 on the front of the flatbed near the truck cab and some customer put a SSB4 on each side of the flatbed for even more storage space. These slant side boxes provided a sleek option