Today on our 2015 GMC Sierra 3500 HD we'll be taking a look at and installing the BAKBox 2 Collapsible Truck Bed Toolbox for BAKFlip Tonneau Covers, part number BAK92120. The BAKBox Collapsible Truck Bed Toolbox is the perfect way to secure your gear and keep your tools organized under your tonneau cover. With the easy no-drill installation and the hardware included, it's designed to fit within… see more >