Kapro Prolaser Vector 873 GREEN Manuel D'utilisation page 19

6) Mark point a2 on the wall, in the middle of the vertical beam at
the same height of a1. (see figure 8).
Figure # 8
7) The distance between a1 and a2, should not be more than
1mm, otherwise to send the laser level to a qualified technician
for repair.
X
a2
2m
a1
X X
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