Since 2015 we have collaborated with Able on a custom Kone permanent filter for the Ratio Eight, designed specifically to optimize extraction of a full batch of coffee (40 ounces). Able has continued to refine the design of the Kone, and in 2020 released a new version. The new Kone brews better, is easier to clean and more durable than ever.Never make a desperate Saturday morning run to the grocery store for paper filters again!