Looking for a value driven, alternative solution to your name brand "factory" replacement UV lamp and sleeve? US Water Filters replacement lamps and sleeves are made in the US to the exact same stringent manufacturing protocols, and are backed by a one-year, no-hassle warranty. The USWF-111044 is a replacement for VIQUA 602810-102 Lamp/Sleeve replacement combo pack used in the VIQUA D4, D4+, D4-V, and D4-V+ systems and discontinued Trojan C, C4, and C4-V systems. The UV lamp needs replacement every 12 months. After 9,000 hours the UV light weakens and isn't strong enough to properly treat your water. Replacing your lamp annually to ensure optimal system performance.

 
The quartz sleeve is an important part of the UV water treatment system. It protects the UV lamp from coming in contact with the water while allowing the UV light to permeate the water. Minerals from the water will build up on the sleeve over time, causing the sleeve to become cloudy not allowing the UV light to permeate the water as effectively.