Galvanized pass-through letterbox for masonry, front plate made of aluminum, steel or stainless steel. Housing and removal door made of galvanized sheet steel. Installation box with intercom grille pre-equipped for all commercially available counter loudspeakers. Light and bell module with lighting. Stainless steel front without plastic on the outside and partially wired. Letterbox 300x110x 265-410mm. Steel front available in all RAL colors for an additional charge (standard color white or gray aluminum). System for 1 residential unit