SunSun JUP-23 submersible UV sterilizer allows simple and effective UV control of harmful microorganisms & free-floating algae. Compact and versatile units are ready to install – no additional tubing or circulation pump required. Built-in pump directs waterborne organisms past the UV-C lamp for clean, clear aquarium water. Install in vertical or horizontal position right in your aquarium or sump. For fresh, saltwater aquariums or garden ponds. Includes UV unit with built-in pump and UV ballast, UV-C lamp, and suction cup mounting brackets