4" DPF & Cat Delete Pipe (Aluminized). Features: 4" Diameter Exhaust Pipe. Mandrel Bent Aluminized Exhaust. Straight Pipe System. Produces Aggressive Performance Sound. Increases Horsepower. Increases Torque. Increases Fuel Efficiency. Bolt-On kit w/ All Necessary Pieces. Requires proper vehicle tuning to install.Diesel Performance