Hyper-secured to handle expansion and vibration Covered by 2-1/2" diameter heat shields Improved horsepower and low-end torque 1-3/4" 16-gauge headers with an obround 1.875" crossover for improved flow 18mm and 12mm O2 bungs welded into the primaries Made in the U.S.A.. HEADPIPE AGGRESSOR M8 BLK