UV light is working great. I didn’t look at the measurements so had planned to put in my skimmer box. The light was almost two feet so had to change my plan on putting in the water. I had a noticeable difference by day 5. I attached the light to a crate I got from a bulb order. It was the perfect size. It is held down with rocks and plants. So far I’m impressed. Shipping was fast and product was packaged well. I’m including pictures to show the 5day difference where it started out green and now I can see the bottom. This is a great product that is budget friendly.