1996-1999 Chevy/GMC Truck, 1500/2500, 1996-1997 Suburban, 1996-1997 Tahoe/Yukon: 5.7L, Tube Size 1.5" O.D., w/o A.I.R.; Silver Ceramic Coated; 50-State Legal header CARB EO #D-115-16.;This is a 50-State Legal header C.A.R.B. EO #D-115-16.; Sturdy 16 gauge tubing; Extra thick 3/8” flanges for a leak-free seal; Designed as a direct fit replacement for factory exhaust manifolds; Will accommodate all emission control devices; Bolts directly to factory head pipe; Complete with premium gaskets and hardware;