Mr. Aqua's 18 watt internal UV light sterilizer is the latest technology in aquatic water treatment. The process is harmless to both freshwater and saltwater plants, animals, and invertebrates. The Phillips UV-C bulb is sealed to allow 100% complete water contact and provide the best treatment against bacteria and germs. Stainless steel surrounds the UV bulb to protect the plastic from heat and to maximize UV exposure to the water. The sterilizer can also be used as a surface skimmer. The Mr. Aqua UV light used with quality Philips UV bulbs guarantee 8000-9000 hours of usage. Warranty Info: All UV lights shall be covered by a 90 day limited warranty. The pump is covered under a 12 month warranty from date of purchase.