Retrofit
LED Retrofit Kits replace existing Metal Halide and Fluorescent bulbs (and sometimes the ballast) within an existing light fixture. Think of a retrofit kit as a LED replacement of the lighting components inside your existing fixture. The difference between retrofitting or replacing an existing light fixture is: Retrofitting is the process of replacing the internal lighting components of an existing fixture with LED components. You keep the existing fixture. Replacing is the process of removing the existing fixture and installing a new LED Fixture in its place.