The three chamber design utilizes Flowmaster's Delta Flow technology along with an internal tuning chamber to reduce sound inside the vehicle. Provides the same performance and exterior tone characteristics as the two chamber, but with less interior resonance. Constructed of 16 gauge aluminized steel and fully MIG welded for maximum durability. Moderate Sound Mild interior resonance Excellent choice for Street Rod cars and trucks Improved Horsepower, Torque and Engine Efficiency MODEL NO - 943053