The Omnipure CL6ROT33 inline water filters contain granular activated carbon to reduce chlorine taste and odor. It is friction-welded together for reliable no-leak seal. Now uses a T40 carbon These are used in ice machines, water coolers, drinking fountains, under the sink systems, and reverse osmosis systems. Specifications: Dimensions: 2" W X 6" L Flow Rate: .5 GPM Maximum Pressure: 125 PSIG Degree of Nominal Filtration: 5 Micron Service Life: 1000 Gallons or 1 Year Volume: 8.3 Cubic Inch Maximum Temperature: 100 F Pipe Size NPT: 1/8", 1/4", and 3/8" **Interchangeably used with T28, T33 and T40 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.