These tips are 4 diameter. angle - cut Carbon Fiber and Stainless steel exhaust tips that give your Porsche an aggressive appearance. The tips are designed with slotted air vents to reduce surface heat. This allows hot exhaust to dissipate keeping the carbon fiber surface cooler. The MACH Force - Xp tips feature a carbon fiber outer wall and 304 stainless - steel inner wall for heat and corrosion resistance. O.E. like fitment allows for a simple, hassle - fee installation with no modifications necessary.