These anodized aluminum rails attach to the inside walls of any GMC/Chev 6’6” bed between 2007- 2014. Depending on later years that have these bed oval holes in the box side the oval spacing has to be 27’ and 34’ from the center toggle hole. They may fit other manufacturer models – need to visually check your truck, measure and compare to pictures attached. They feature adjustable cleats that slide along the rail system every four inches to secure cargo of various sizes at various locations throughout the bed. They are attached to the inner bed by a toggle bolt system where the cleat fits into the existing factory designed oval holes in the sides and front of the box. There are some original parts/stock still available thru GM parts. If you want to see schematics and parts for this system search “ Kipp Sc…” - “ Box rails for 2014 GMC Sierra 2500 HD” This factory and/ or after market system retailed for over $2K. I have swapped out my original box and no longer need this system so selling. Everything complete/working and intact. Asking $275. West Edmonton location. If ad is visible this hardware is available.