Hans Grohe AXOR Citterio M 34444 1 Series Installation Instructions / Warranty page 7

Grease the diverter o-rings with the enclosed lubricant.
Push the diverter firmly into the spout tee.
Place the sealing ring, escutcheon, and flange over the
diverter stem.
Push the spout into place.
Tighten the spout screw with a 3 mm Allen wrench.
Install the diverter knob.
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