Adjustment ring that allows you to adjust the granulometry of the coffee with greater precision than in the past. Aesthetically, the new ring improves the readability of the adjustment setting through a visual indication with a micrometer scale and an absolute precise reference of the zero position. An arrow indicates the correct direction to adjust the grain size of the grind. In addition, the new ring allows you to vary the distance between the burrs continuously with micrometric accuracy, allowing for more effective extraction of volatile substances to obtain a coffee with an excellent aromatic profile. The adjustment ring is made of technopolymer with metal nanoparticles which give an appearance and a tactile perception comparable to a detail made of metal material. The new regulation system – patented – is completely independent from the grinders and therefore allows you to make adjustments even during grinding in total safety.