AquaTru - Replacement 2 Stage Pre-Filter (Stages 1 & 2) for Countertop Reverse Osmosis Water Filter Purification System (AquaTru Classic, Connect & Under Sink AquaTru Water Purifier)Specifically designed to fit in the AquaTru Countertop Water Filter Purification Systems (Classic and Connect) and the AquaTru Under Sink Model. Part AT2001 is Not made for the AquaTru Carafe. Certified to NSF Standards Dual Replacement Filter combines the Sediment Pre Filter and the Activated Carbon Pre Filter into one AND removes odors and conditions the water and reduces sand, silt, sediment, rust and particles. Stage 1 (Sediment Pre Filter)