The Omnipure K-Series K5533 inline filter is a post R.O. GAC inline filter. It comes in 1/4 FQC and 1/4 FPT fittings. It can also be used in ice makers, refrigerators, beverage equipment, drinking fountains, under the counter systems, R.O.Systems and in conjunction with purification systems. This filter aids in the removal of taste, odor and chlorine taste and odor. Dimensions: 2.5" W X 10" L Flow Rate: .5 GPM Maximum Pressure: 125 PSIG Maximum Temperature: 100 F Service Life: 1 Year or 2000 Gallons Filtration Media: Granulated Activated Carbon Volume Cubic Inch: 28.6 Fitting Size: Quick-Connect 1/4" fittings and 1/4" FPT fittings Omnipure K5540-JJ has been tested for performance under NSF Standard 42. **Interchangeable carbon with T28, T33 and T40 models. 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.