See more about this article : Emperor Aquatics T5-UV Lamp - 25 watt

The 25 watt Replacement UV Lamp for various Emperor Aquatics, Inc. aquarium UV Sterilizers, such as the 25 watt SMART UV Lite and the 25 watt SMART UV Sterilizer, is made of high quality quartz glass and offers 13 months (9,000 hours) of continual operation of lamp life. The 25 watt ultraviolet lamp has a length of Length of 18.5" and a diameter of 0.75".

NOTE: All UV Sterilizer gaskets and o-rings must be replaced annually to ensure a watertight seal.