The TrojanUVMax™ 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 TrojanUVMax™ systems have a one year life while the high output amalgam based lamps that are used in the TrojanUVMax™ 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. Systems used in: C C4 D D+ D4 D4+ Lamp Life: 9 000 hours (1 years) Description: Low pressure high output lamp with a black base