The fixed sleeve is sealed in the masonry with a slight outward slope (this sleeve can be cut to the thickness of the wall). The 200 mm length adjustment sleeve crosses the interior lining. The sleeve associated with the grille fits into the fixed sleeve.
Provide an overlap of at least 20 mm between the fixed sleeve and the adjustment sleeves and an overhang of the adjustment sleeve on the inside of at least 30 mm for the duct connection.
