Review on OptiCharco Filters: The Ultimate Keurig Replacement by Erin Dudley

It contains powdered activated charcoal, like the brand name, is the same size and (as far as I can tell) acts the same. The price is lower than the brand which makes it a bargain. I just used the first of the filters. When soaked before use, the water turned black. Repeated soaking[4] was required to prevent the charcoal from seeping into the water. I assume the charcoal removes any contaminants and taste/odor that may be in the water, but the material wrapped around the filter appears to be much more porous than a Keurig brand filter.