Activated carbon is a form of carbon that has been treated with oxygen to make it very porous, allowing for a larger surface area for chemical reactions to occur. The carbon absorbs organic materials and Chlorine from the water it comes into contact with. What's in the box 3x Inline Taste and Odour Filters with 1/4" threaded ports (Please note that this is not a fridge filter and it does not include Easy-Fit fittings)