Borla 140429 Cat-Back System It fits Silverado/Sierra 1500 '09-'11 4.8/5.3L/6.0L V8 AT/MT 2 and 4 wheel drive 2.25 inch piping diameter, single round half rolled phantom angle cut and split rear exit Ultra-smooth mandrel bends ensure maximum flow and power It is a S-type Cat-Back system