What is the preferred lockable single mailbox for postal carriers?

These mailboxes have outgoing vessels within the top slot of the mailbox, it has a double slot, one for outgoing one for incoming Please look

This sturdy Dancy mailbox keeps all your post secure thanks to the lockable mail slot and weatherproof steel build The powder paint finish means it will stand

locked money box with slot DEAYOU Wall Mount Mailbox, Steel Cover Metal Drop Box, Mail Box with Key Lock, Dropbox with Slot for Envelope, Home, Office Business, Decor, Black Wall

locked mailboxes with slot Mail Drop Slot & Receptacle +- Mail Supply will assist you with choosing the most practical locking mailbox for your residential, commercial or