Fellow Prismo AeroPress Filter Overview Especially designed for the AeroPress coffee maker, the Fellow Prismo AeroPress Filter is a pressure-actuated valve that allows for the build-up of pressure for espresso-style coffee. For recipes that call for an inverted AeroPress, the Prismo AeroPress filter creates a no-drip seal. A reusable 150 micron etched metal filter stops fines and used grounds from entering your cup, only needing a quick rinse after each brew.