The Lifegard Aquatics 25W GT5 UV Sterilizer Lamp for the 25W QL-Series UV sterilizers, Pro-MAX 3" Body 25W Standard High Output UV Sterilizer, and the Aquastep Pro 25 Watt UV Sterilizer. This lamp will not work with the old style Aquastep 25 Watt UV Sterilizer.
