STD-4B+ and Private Horizontal
STD-4B+ USPS and Private Delivery Horizontal Mailboxes

Changing postal standards can raise a lot of questions for anyone who deals with apartment mailboxes. The dilemma for property managers is whether to install Security Upgrade Kits in existing mailbox units to comply with STD-4B+, to get new mailbox units in compliance with STD-4B+, or to upgrade mailboxes to STD-4C. How do you decide? One easy way is to ask your local postal carrier. They may have recommendations to improve the security and convenience of your mail—a benefit to property managers, residents and the Postal Service alike.

It's always a good idea to get the approval of your local postal authority before altering the mail system in your building; but in general, if your project is not disturbing the wall the mailboxes are already mounted in, then replacing old mailboxes with a product similar in style is typically acceptable. Any adjustment to the rough opening in the wall will require new STD-4C compliant mailboxes.

If residents would like to increase the security of their existing STD-4B products without doing a complete mailbox replacement, Florence offers a STD-4B+ security upgrade kit for its mailbox products. While not able to fully bring the security up to the new STD-4C standards, these upgrade kits will enhance the security of the existing STD-4B box by hardening the arrow lock master door; typically the most vulnerable portion of older mailboxes.