These upgrade shafts feature a huge 6.5mm shaft diameter and strengthen the threaded shock ends massively compared to stock. The PowerStroke HD Shaft has been coated with a titanium carbon nitride (TiCN) coating which further hardens the shaft surface and reduces stiction. Integrated shock guards protect the shafts from rocks, dirt and mud and adds style to your truck. The PowerStroke HD Shock Shafts come pre-built, so you just need to install and bash on! The pistons and shaft guides are made from white delrin for smooth operation and an optional smaller hole piston is included for added tuning options. The larger shaft is made to work with the stock X-MAXX shock cap, but it also pairs perfectly with Pro-Line's Ultra Reservoir Shock Caps for even better performance!