Built-in letterboxes, flush-mounted version. Insertion and removal from the front. Box and door made of galvanized sheet steel, insertion flap made of aluminum. Aluminum round profile frame RS 3000. Installation box with intercom grille pre-equipped for all standard counter loudspeakers. Light and bell module with lighting. Available in all RAL colors for an additional charge. Powder-coated. System for 1 residential unit, box format 370x 330x 100mm. Complies with DIN EN 13724.