Replacement filter for QCRO and QCUF Systems. Made in the USA. For maximum performance, replace filter every 6 months or 2000 gallons. Reduces chlorine taste and odor. The RO-QC-450-CBRF Tier1 4-Stage Carbon Block Quick Change Reverse Osmosis Water Filter Replacement is a replacement filter for Tier1 RO-QC-450, QCRO, and QCUF systems. This product reduces chlorine taste and odor that may be found in your drinking water. It's recommended that you replace the filter every 6 months or 2,000 gallons for cleaner, better tasting drinking water.