authentic US mailbox

Typical design for this mailbox of fulton illinois establishments in metal (steel?) galvanized. It does have its little red flag that the postman points out to indicate that he has placed letters inside and that the box is lowered once the box has been emptied. It closes without difficulty by a valve with a mechanism as simple as effective and the mail stays dry. To be installed both outside and inside (holes are provided for a horizontal attachment). And, eventually, to divert: a nest box in the garden. A box to store your keys inside. Inside was still an old purchase order to customize the mailbox. Dimensions: long 48; 16g; 22 cm high. Minimal traces of use on the outside, very clean interior. Looks like it never served...