CLEARRAY UV-C Technology treats water with the power of nature-inspired ultraviolet light to neutralize water-borne pathogens. Ultraviolet light disrupts the DNA of bacteria and viruses. This process occurs in a small water-treatment chamber, away from bathers. All water from your hot tub circulates through this chamber and emerges clean and sanitized. The result is clean, clear, fresh water. Using the CLEARRAY Water Management System to sanitize your hot tub will save you money in other ways, too. Water treated with UV wavelengths of light needs less chemical treatment. You’ll be able to use about half the chlorine, bromine, or minerals. See the manual that came with your Sundance Spa. CLEARRAY XL Bulbs are manufactured by Sundance Spas for use in both Sundance Spas and modern Jacuzzi hot tubs that feature the Clear Ray sanitizing system. Made in USA.