Grohe Axor Uno Wall Mounted Single Handle Lav Set 38118XX1 Installation Instructions Manual page 7

Connect the fixation nuts to the sleeves.
Measure the distance from the rough to the outside
surface of the finished wall (X) (1).
1.
Add 1" to X. Cut the threaded end of the spout so that
it is X + 1" long ().
2.
X + 1"
Push the baseplate against the wall (1).
Thread the sleeves into the rough ().
2.
1.
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