PLM ( Private label Mfg. ) Axle-Back exhaust also known as Muffler Bypass, Muffler Deletes, or Track Pipes are made of tig welded stainless steel, lightweight compares to factory mufflers, and sounds amazing! Made for Subaru WRX / STi, years 2015 to present models, V2 (Version 2) now fits 2020 models and features a more aggressive, bigger, better 4" stainless steel exhaust tips. The piping of this track-pipe has an OD (Outer Diameter) of 2.5" / 65mm ending with dual 4.0 inch single wall staggered tips.Dual exit for the most direct exhaust path, with easy & quick 15-minute install using only hand tools.Options: Blue-Titanium Burnt Tips or Polished Tips For Subaru WRX / STi VA 2015 -2021 Direct bolt-on easy installation to OEM mid Y pipe This product will NOT fit other aftermarket exhaust systems Will NOT fit SPT model. 2.5 inch, 16 gauge, stainless steel, mandrel bent pipe Precision CNC Mandrel Bent 4 inch single wall staggered tips OEM style exhaust hanger rod constructed High quality hand TIG welding Lightweight compares to the factory mufflers One year limited warranty CNC machined flanges Flange is .38" / 3/8" thick 18 gauge on the stainless steel piping.  Measured at .049" to .050" Installation Note:  Use factory gaskets for installation.