Introducing three new submersible Ultraviolet Clarifiers with the glowing monitor halo ring that immediately shows it's working. The only ultraviolet lighing that's submersible, it can also be placed outside of the pond. The black colour makes it unobtrusive wherever it's used. Visible during the day and night from any angle, the soft blue halo shows it's working, but also does not detract from the beauty of your pond. Designed to handle the clarifying needs of ponds up to 6,000 gallons. These lights offer great value, along with ease of use unsurpassed by any other ultraviolet sterilizer. UL listed to Canadian and U.S. safety standards.