A naked portafilter for the 9Barista espresso machine.
The naked portafilter has a larger aperture than the standard portafilter, giving a full view of the extraction. The benefits are partly aesthetic, but the full view of the basket can also help identify channelling, which is helpful when identifying how to improve shots.
It's worth noting that using a naked portafilter does require some careful puck preparation. Without this you may experience 'spritzing', which is where very fine jets of coffee spit from the portafilter as a result of channelling. Careful distribution and tamping of the coffee prior to brewing resolve this.