Banks Power Boost Tube Upgrade Kit (2017-2019 GM HD 6.6 Diesel)Banks massive 3. 5in boost tubes are the largest charge air cooler pipes on the market, flowing 680 CFM and 87% more air than stock! Smooth mandrel bent tubes deliver more air to your engine while reducing boost pressure loss resulting in quicker turbo spool and more power. 50 State Compliant CARB E. O. D 161 155 Key Features Huge increase in size and flow over stock and competitors (3. 5" vs 2. 5") Billet venturi couplers maintain boost pressure