Coralife 08604 Lunar Aqualight High Output T5 Fixture (24inch) spray collar refill poly elastomer strap that is integral poly elastomer strap that is integral with the radio box and you've got THE state of the art electronic collar at an amazing value Water is pumped into the sterilizer chamber where ultraviolet light eliminates the unwanted microorganisms resulting in a clean and clear aquarium Lunar Aqualight High Output T5 Fixtures include four high output lamps and directional LED moonlights making these fixtures a great choice for saltwater reef tanks The directional LEDs can be positioned to add a shimmering moonlight accent over a specific area in your tank or the LEDs can be set to provide a more even distribution of moonlight