aFe 3in SS Cat-Back Exhaust GM Sierra 1500 (09-18) (49-44111-B)aFe POWER introduces the Apollo GT Series cat back dual rear exit exhaust system for the 2009 2018 Chevrolet Silverado GMC Sierra 1500 with V6 4. 3L & V8 4. 8L 5. 3L engine. This dual exhaust system is constructed out of 3" 100% MIG welded, mandrel bent, stainless steel tubing for maximum flow. The smooth transition bends allow for low turbulence, increasing horsepower, torque and improved throttle response. A free flow single in dual out muffler is