Viega Prevista Dry Plus 8545.31, Instructions For Use Manual, Page: 8 / 11

The two vertical rails, which surround the module, must be
open towards the module and have an inner distance of
420 mm.
Secure the module onto the open mounting rail with the slot nuts
supplied.
Insert the slot nut into the opening of the module.
Push the slot nut in until it engages.
Set the height of the rail.
Handling
Prevista Dry Plus washbasin module, barrier-free 8 from 11