This replaces the power connectors/bulb holders with something more compact. Extra pin holes are removed, the third pin (for connecting to backroom notification systems) is removed, and unneeded bulk is removed. So if you have to replace yours due to a broken bulb holder, this is for you! Just swap the two primary power pins and fuse clip over to the new one and you're good to go. If your bulb's rubber grommet is rotten, replace it with the one here, just print it in TPU. It's not a super tight fit, since TPU doesn't have the same amount of give as soft rubber, but if it won't stay put, just a tiny drop of CA glue will hold it in place, yet still allow you to remove it fairly easily.