Kapro 883N Prolaser 3D All- Lines Manual Del Usuario página 20

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.
4. Checking the Accuracy of the side Vertical beam (#5).
For the second vertical beam repeat the previous marking
procedures from paragraph 1 -7.
20
X
2m
Figure #6
a2 a1
X X
6