Product Description The D-20A Basic drinking water cartridge provides up to 12 months or 1,000 gallons of refreshing drinking water by reducing chlorine and bad taste. The D-20A filter is compatible with the Culliga US-550, RO-2127 and US-600A filtration systems. This Culligan D-20A filter offers level 1 granular activated carbon and has a high surface area for maximum adsorption. With a Plumbed-In Reverse Osmosis System, this filter will make sure you and your family always have access to clean and delicious water. The filter is NSF Certified and has a 2-year warranty. It also includes a change reminder sticker and is recommended for city and well water supplies. From the Manufacturer Culligan D-20A Level 1 granular activated carbon drinking water filter cartridge reduces chlorine, bad taste and odor. It has a high surface area for maximum adsorption and has a filter life of up to 12 months or 1000 gallons. This filter cartridge fits model numbers US-550, US-600, US-560, US-560K, CTR-210, SY-5167, and RO-3167 Plumbed-In Reverse Osmosis System. The filter is NSF Certified and a 2 year warranty. It also includes a change reminder sticker and is recommended for city and well water supplies.