Professional barista funnel has a 3/4" deep spout with a 57 millimeter outer diameter. It fits snugly into 57, or 58 millimeter portafilters (see inset photo). This is like the IDR, except with a much broader input!
The 3/4" spout depth allows it to sit completely within the portafilter basket for stability. The mouth of the funnel is 5.5" in diameter, which gives ample room for you to pour doses of espresso into the portafilter without making a mess.
While this barista funnel will keep any barista's space neat and clean, this professional funnel is EXTREMELY useful within you home, where you really don't want to make a mess.
Simply insert the barista funnel into your portafilter, dump in the ground coffee, and tap the portafilter base on your tamping mat to drive all of the grounds into the portafilter basket. Then remove the funnel, and tamp.
It couldn't be any easier - or any neater! Note also that the final tapping of the portafilter (with the funnel inserted) will result in a LEVEL mound of coffee in the portafilter to begin with. In addition to avoiding any mess, this ensures a uniform compression of your puck when you tamp it down.