The Omnipure K-Series K2350 inline filter has 1/4 FPT and 3/8 FPT fittings on both sides. This filter has KDF-55 in it to help reduce specifically chlorine, and heavy metals. It can also be used in refrigerators, ice makers, any under the counter reverse osmosis or water filtration unit. Dimensions: 2" W X 6" L Flow Rate: .5 GPM Maximum Pressure: 125 PSIG Maximum Temperature: 100 F Reduces: Chlorine Taste Odor Reduces: Scale, Bacteria and Algae Filtration Media: Granulated Activated Carbon with 1/4 lb. KDF-55 Fitting Size: 1/4" FPT and 3/8 FPT National Pipe Thread (NPT) Size Measured Against a Ruler* Actual Diameter (Inches) National Pipe Thread (NPT) (Fractional) 0.405" 1/8" 0.540" 1/4" 0.675" 3/8" 0.840" 1/2" *NOTE: A very common misconception is that a 1/4" NPT measures as 1/4 inch on a ruler or tape measurer. However, that is not the case. NPT will measure larger in diameter. Above is a sizing reference to help clarify.