The LP640 Mercielago Test Pipes are hand crafted and built using 304L Stainless Steel. These test pipes are designed to direct all exhaust gasses through the main exhaust section prior to exiting the tips. The importance behind this method is to send exhaust notes from both banks to the main exhaust section to intermix them together, instead of having both banks shoot exhaust notes out the tips with a non 12 cylinder intermixed exhaust note. Intermixing the 12 cylinder exhaust notes will increase the high pitch sound coming from the v12. If you are looking for that notorious high pitched formula 1 v12 scream, then this is the test pipe selection you will need to accomplish that next level exotic sound.