This door has a vertical mail slot : rmildlyinteresting

vertical mail slot   Dan vertical mail slot

Mail Slot, x 11 x Inch Size, Vertical CE7HFV Worldwide Delivery +44 203 287 5224

Front Door Letter Mail Slot Vertical letterbox vertical slot and provided with holes for engaging with the catches , and MAIL

auto wallet slot For people who cannot get to an outside mailbox, horizontal mail slot mailboxes are relatively cheap and can be installed on doors or through a wall  Bronze “Letters” inscribed door mounted mail slot with back