The Viqua lamps are offered as a high output mercury vapor or high output amalgam based depending on the UV model. Both lamp types offer reliability and stability giving off the most amount of UV intensity in a compact design. The high output lamps that are used in the Viqua systems have a one year life while the high output amalgam based lamps that are used in the Viqua Pro and Light Commercial series offer a two year lamp life. All VIQUA lamps are designed to operate with a specific ballast so be sure to GET GENUINE and contact your dealer in order to order the correct lamp when it's time for replacement.