The Omnipure K-Series K5621 inline filter is a 10 micron carbon block inline filter. This filter comes in 1/4" FPT and 1/4 FQC quick connect fittings. This filter 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 sediment, taste, odor and chlorine taste and odor.
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.