Our PRG/Sway-A-Way 2.5-inch piggy-back rear shocks are custom built by Greg at PRG. He orders the parts, builds the upper mounts, valves them, and machines custom inner parts to make the work properly. Greg valves each shock himself to his specifications for each model truck. The new shocks bolt into the stock locations. On top of the obvious benefits of having a larger shock under your truck, the new shocks are completely rebuildable. Unlike stock shocks which can fall apart from abuse, these shocks will take a severe amount of beating and if they ever do fail, all parts can be replaced with ease.