1. Fully TIG welded, all flanges, no gas leaking. 2. #304 stainless steel muffler with single #304 polished tail pips 3. 304 Stainless steel Flanges can be match ported 4. Build in M18 nuts, for tuning when use O2 sensor 5. Fit under rear apron for type 4 engine baywindow bus pre1979 6. For Type 4 engine up to 125HP. 7. Include Gaskets set for muffler. 8. Muffler will clear original tow hook.