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Vertical Mailboxes - USPS-STD-4B+ compliant mail boxes

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USPS Approved Replacement 4B+ Vertical Mailboxes

Florence 4B+ vertical mailboxes are USPS approved for replacement / retrofit purposes only. These units are for indoor use only in small multi-family buildings & apartments. You may choose recess mounted or surface mounted versions. If you have any questions about compliance or installation info please give us a call and we'll help fill in the blanks.


3-Door 3500 Series Vertical Mailbox Product Number: 3503 $143.00 Full Description
4-Door 3500 Series Vertical Mailbox Product Number: 3504 $190.00 Full Description
5-Door 3500 Series Vertical Mailbox Product Number: 3505 $238.00 Full Description
6-Door 3500 Series Vertical Mailbox Product Number: 3506 $286.00 Full Description
7-Door 3500 Series Vertical Mailbox Product Number: 3507 $334.00 Full Description

Florence 4B+ vertical mailbox features:

  • USPS Approved for replacement purposes only! Please consult with your local Postmaster prior to ordering
  • All Vertical mailboxes are designed for use inside small multi-family buildings and are for indoor use only. They are not designed to be used outdoors – check with your local Postal Officials.
  • Vertical mailboxes are available in 3, 4, 5, 6 or 7-door configurations only.
  • Constructed of durable, heavy-gauge extruded aluminum - Doors and trim are striated to resist scratching.
  • Two Vertical Mailbox installation options – Choose from A) Recess mounted (requires 7 ½” wall depth) – Click Here to view an illustration; or B) Surface mounted (protrudes 7 ½” from wall) - Click Here to view an illustration. See individual product details for line drawings of specific product. Installation hardware is not included.
  • Designed to meet the USPS STD-4B+ specification, the 3500 Series has stronger compartment locks and master doors that better resist the more common methods of tampering.
  • These boxes are ideal replacement options to ensure your residents continue to have safe and secure mail delivery options.
  • Click Here to view some product features.
  • Standard compartment size is: 16 ¼” high x 5-1/2" wide x 6 ¾” deep.
  • The 3500 Series includes 5-pin cylinder tenant locks with two keys, and a 2-1/2'' wide x 5/8'' high indentation to accommodate a label (included) to identify the tenant’s name and/or box number.
  • Choose from USPS access, or Private Delivery ($27.50 upcharge for private use master lock).
  • Features a durable powder coated finish available in Aluminum, Brass, Bronze, Sandstone or Green. Click Here to view a color chart.
  • Need an outgoing mail compartment? Buy a Vertical Mailbox module containing one additional door, then add the outgoing mail slot option - $10 Upcharge applies – Mail Slot is placed in the furthest left-hand side door. Click Here to see a picture of a door with an outgoing mail slot.
  • Click HERE for the 3500 Series product data sheet.
  • Click HERE for the installation instructions.

Multifamily Indoor Vertical Tenant Mailboxes

US Mail supply’s 3500 series are USPS-approved and designed for many multifamily complexes. This would include apartments, condos, office building and any location with a USPS mail distribution center. Anytime you’re dealing with private documents or packages, security is utmost important. This is why our lockable, vertical mailboxes, are constructed of durable, heavy-gauge aluminum. The vertical mailboxes are ideal to keep residents mail safe and secure.

Each door comes with two keys, and for each unit there’s one master lock. The master lock opens all doors therefore, delivering mail is easier and faster. The 3500 series also includes labels to identify tenant’s names. This avoids confusion when mail is hand delivered.

Durable, Lockable, Vertical Mailboxes for Apartment Use

Installation is easy and painless. You can recess mount or surface mount. The recess mount requires a 7 ½” wall depth. Surface mount requires protrusion of 7 ½” from wall. After the unit is set up, you should contact USPS. USPS will provide and install its own master lock. More instructions on installation can be found in product details section above in red.

If you have any questions in regards to installation, customization or products detail please contact us right away.

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