This is the footpedal. Kees v/d Westen installed it on the Mazzer. I’ve tried it and it’s realy easy going. Now u can use one hand to hold the portafilter and the other hand to dose the ground coffee. Once you feel that there is enough coffee in the portafilter just take your foot of the pedal.
I will ask Kees to give us some more technical info about the installation.
You can watch Kees amazing work on www.keesvanderwesten.com