Replace the Polyphonic Harmonizer behind the muffler in the ATAK system with this muffler to attain the "S-Type" sound level (quieter than ATAK). Built from premium T-304 stainless steel, superior to T-400 series knockoffs (such as 409), to give you the absolute best in performance and durability. Ultra-smooth mandrel bends ensure maximum flow & power, and precision computer-controlled CNC manufacturing ensures an accurate fit.