What is the preferred lockable single mailbox for postal carriers?

Locking Mailbox Inserts adds a secure locking compartment to standard 6” or 8” wide post mount

The steel mailbox features a locking hinged door for security It features a top slot that measures 10 12 x ¾ Mailbox is wall mountable

locked money box with slot Note: A mailbox with a lock must have a slot that is large enough to accommodate your daily mail volume The Postal Service™ neither opens a locked box nor

locked mailboxes with slot VEVOR 2Hp Belt Grinder Constant Speed 2 X 82 inch Belt Disc Sander with 3 Grinding Wheel 110V Bench Sander 12 inch Wheel and Flat Platen Tool Rest for Knife