What each family highlights
The belt (PROFI B Vario, PROFI B 350): the basic workshop machine, which combines pre-grinding, structural grinding and edge grinding. The sheets mention a storable program and pneumatic grinding pressure.
The stone (PROFI S 200 and 350 Racing): geared to race structures, with a library of factory structures, a structure advisor and an 8 inch colour touchscreen. The S 200 is for skis only, the S 350 for skis and snowboards.
The combined machine (Profi 4 Racing): 350 mm belt and stone in line in a single machine, switching from one to the other at the press of a button according to the manufacturer description.
How to decide
Start from your structures: if the workshop mostly prepares rental and customer skis, a belt is often enough. If racing or a high level of customisation matters, the stone brings the structure library. If you have room for only one machine and need both, the combined machine avoids duplication. The guide to ski base structure details what structure changes.
All pneumatic machines need 400 V and compressed air: see the NUAIR compressors. The complete range is in the ski base grinders.