Smart UV Sterilizers from Emperor Aquatics are watertight and safe to operate both indoors and outdoors. These UV's are designed for fresh or saltwater aquariums and pond applications. Each Smart UV Sterilizr is constructed of heavy wall UV resistant plastic that increases durability and longevity. The Emperor Aquatics Smart UV Sterilizers comes in three styels. The Smart UV Lite Sterilizer, 18w, 25w, 40w, with or without a quartz sleeve wiper. The Smart UV Sterilizer, 25w, 40w, 65w, featureing a quartz sleeve and pure hard quartz lamp. The High Output UV Sterilizer, 50w, 80w, 120w, 150w, these units use a T6 style high output lamp.