2 part frames can be installed using the patented BOS levelling anchor and its special levelling screws without underlay. The levelling screws can compensate for tolerances up to +5mm.
Due to the adjustment area no anchor underlay is required and any possible dimensional inaccuracies of the wall are simply corrected. A backfilling of the frame is not necessary.
The levelling anchor is suitable for all wall types and guarantees maximum stability with its steel sheet strength of 2mm.