The GE FXULC single stage under sink drinking water filter replacement filter is compatible with the following systems: GX1S15 GX1S01C GN1S15C GN1S20C GX1S04C Culligan US-550 D30 D40 Reduces chlorine taste & odor, cysts, asbestos, turbidity, sediment and rust. The FXULC reduces the following from your water 89% of Atrazine 90% of Mercury 98% of Lead 92% of Lindane 99.99% of Cysts 97% of Chlorine taste and odor 99% of Asbestos 99% of Turbidity Class I Particulates Rust The GE FXULC single stage water filter should be replaced every 6 months or 600 gallons.