The Aqua-Fresh WF425 is a compatible replacement for the WF3CB. It contains a filter key to ensure the filter is locked in place tightly, with dual o-rings on each side for an extremely tight seal, sure to prevent leaks when installed correctly. The system has been tested according to NSF/ANSI 42 for the reduction of Chlorine taste and odor. The concentration of the Chlorine was reduced to 2.0 mg/l +/- 10%, as specified in NSF/ANSI 42. The Aqua-Fresh WF425 also carries the IAPMO R&T Water Quality Platinum Seal, as well as a 30 Day Limited Warranty. The WF425 will provide you with 300 gallons or 6 months of clean, clear water from your refrigerator's water and ice dispenser. Maintain quality and performance by replacing regularly, every 6 months. NOTE: While the tips on the end of the AquaFresh WF425 look different from the PureSource3 WF3CB, the AquaFresh model DOES fit.