Question about Zyliss Drum grater set

The plastic at the bottom is loose so that a vacuum can be created when the lever is tilted backwards. Needs some force. So it is not a click system. It is essential to make sure that the standing surface is absolutely flat and clean. For us, the unit holds immovably. We are very satisfied with the drum grater.

So the plastic must be a bit loose. On an even surface made of stone, a little moisture on the plastic and it becomes extremely tight. This does not work on wood, of course, because the moisture is sucked in by the wood and therefore there is no "vacuum/vacuum" formation.