This high quality 100% Coconut Carbon filter is the exact filter we use as our front-line carbon filter. As a rule it is difficult to find 100% coconut carbon filters. Most lower priced filters on the market are a blend of coconut carbon and coal based carbon. The problem with coal based carbon is that it has a shorter life and often results in a less palatable flavour. We use this 100% coconut carbon filter in all of our pre-assembled kits.