Polaris™ Scientific GL24PP Replacement UV Lamp – UVA 6C Filters for 10 inch Big Blue Housings while the 4 stage G3RO configuration while the 4 stage G3RO configuration adds a 50 GPD reverse osmosis membrane for well water or high TDS sources The combination of granular activated carbon and KDF 55 media makes this cartridge ideal for municipal water sources with chlorine and dissolved heavy metals like lead Genuine single end 4 pin germicidal UV lamp for Polaris Scientific UVA systems 💡 Tip: Replace the lamp every 12 months and clean or replace the quartz sleeve at the same time to keep UV output at full disinfection strength