This Black Anodized Exhaust Trim Ring will give an extremely clean finish to the body panel you are passing your exhaust through (see picture in ad). For safety and weight reasons it has become very popular for turbocharged, supercharged, nitrous, as well as naturally aspirated cars to run exhaust out of your fenders/or other body panels instead of shooting exhaust on the ground where it can potentially spray oil, fuel, or moisture on the ground where your tires will run over it. This ring is cnc laser cut and are 4.5" ID which gives a perfect .25" on each side of a 4.0" exhaust pipe passing through. Included in the kit are one stainless trim ring, as well as 1/8" pop rivets for clean and secure installation.