According to the degree of maximum compression exerted (at the heel), it is possible to divide the socks into compression classes.
The international reference standard RAL GZ 387 provides for the following subdivision:
CLASS | Compression type | Compression exerted at the ankle |
CLASS 1 | light | 18-21 mmHG |
CLASS 2 | medium | 23-32 mmHG |
CLASS 3 | strong | 34-46 mmHG |
CLASS 4 | very strong | 49 mmHG e sup. |