This kit includes the replacement UV lamp bulb and accompanying quartz sleeve for the VIQUA G, G+ and Pro10 Model systems. It is extremely important to replace the bulb every 24 months to maintain proper system efficacy. The included amalgam lamp that provides higher strength and up to 2 years of lamp life. The sleeve can be replaced every 24 months or as needed to keep mineral build-up from hindering the lamp's effectiveness.