Grand Rock Powerflow Diesel Pickup Dual Stack 5" Aussie This Is A Complete Grand Rock Diesel Pickup Dual Stack Kit Includes 2 36" Aussie Chrome Stacks This Kit Has A 5" Diameter, with a 4" Dia below the Y Pipe Includes Everything You Need To Give Your Diesel Pickup a "Big Rig" Look Improves Truck Performance With A Better Exhaust Flow