When carbon fiber isn't excessive enough, you want to add them as your exhaust tips! The exterior shows a nice carbon fiber. These tips are 2.5" inlet and 3.5" outlet. These tips are made to slip onto E series and after series NON M or NON M Performance mufflers Each set is sold in pairs. If you need 4 tips, you will need to buy 2 pairs. The metal is made of 304 stainless steel for maximum durability and anti rust protection. Clamps are included. You can clamp or weld them on. These will also fit E series as well.