The ideal brush for keeping the portafilter clean. We can only recommend it!
We use the approx. 35mm wide brush with natural bristles for cleaning portafilters, even though the manufacturer actually designed it as the JoeFrex Mill Brush Maxi for cleaning large grinders. For cleaning espresso and coffee grinders (e.g. Comandante C40) we prefer to use the "small" JoeFrex grinder brush.