This replacement set includes the replacement UV lamp and quartz sleeve for VH410 as well as necessary o-rings for installation. This pairing of necessary components is ideal for situations when an overhaul of your UV system is necessary. The quartz sleeve is an important part of the UV filter treatment process, it surrounds the UV light preventing it from coming in contact with the water. UV light is transmitted through the quartz sleeve and purifies the water. Over time the sleeve will accumulate minerals from the water which must be cleaned to prevent the UV treatment from becoming less effective. Once the mineral layer becomes permanent and can not be removed the sleeve needs to be replaced. UV lamps should be replaced every twelve months to ensure the highest quality and purity of water. No need to worry about your VH410 system with this convenient replacement kit, order yours today!