This is a 2.0"x10" Granular Activated Carbon (GAC) inline water filter (1/4" FPT) by Kemflo. GAC will remove (by adsorption) chlorine, odor and organic matter from water.
This element is used as a final polishing filter in most undersink reverse osmosis systems and the bottle-less water cooler). It can also be used as inline filter for water flow into icemakers, refrigerators, drinking fountains.
The flow capacity in this standard size cartridge is 0.5 gpm.