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Salsbury 3504BSU 4 Door Vertical Mailbox Brass Finish Surface Mounted USPS Access

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SKU: WL-3504BSUBM  |  View All 4 Door Surface Vertical Mailboxes
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List Price:
You Save:

$54.03 (20%)

Volume Discount Pricing
2 - 5$203.50
6+ $183.67
Per the USPS standards, vertical (4B) mailboxes are only to replace existing vertical (4B) mailboxes. All new construction should use 4C Cluster Mailboxes, per USPS regulations. We strongly advise that you discuss installation with your local post master.
According to manufacturer:
Usually ships in 1 to 3 business days
Custom Engrave ships in 1 to 2 week
Ships directly from the factory floor to ensure the quickest available delivery.

Overview of Salsbury 4B+ Vertical Mailboxes

Salsbury's 4B+ Vertical Mailbox units are an ideal mail solution for apartments, condominiums, commercial buildings, and anywhere multiple tenant boxes are needed. Available as a surface mounted or recess mounted unit, the streamlined design can be stacked two units high if wall space is limited.

The top-loading system can be utilized for either USPS or private use and allows for ease of use when depositing mail. The access door unlocks the entire compartment array, which slides forward for easy mail drop-ins.

With its durable powder coat finish and all aluminum construction, Salsbury's vertical mailbox will provide years of reliable, maintenance-free service.

Features & Specifications


  • Ideal for apartments, condominiums and commercial buildings
  • Approved to the required security upgrades of USPS-STD-4B+
  • Manufactured to USPS-STD-4B+ specifications
  • USPS approved for replacement and/or retrofit installations
  • For either USPS or Private Use
  • Mailbox units are available with 3 to 7 vertical mail compartments
  • Top-loading mailbox: access door unlocks the entire compartment array, which drops forward for fast and easy mail loading
  • Tenant retrieves mail by opening individual vertical door (mail compartment is 6 ¾ in. deep)
  • Available as Surface Mounted or Recess Mounted Units
  • Mailboxes should be shielded from direct weather conditions, so it is recommended that these units be installed indoors only.

Materials and Finish

  • Mailboxes are constructed entirely of aluminum
  • Each door has a durable powder coated finish available in 5 contemporary colors:
    • Aluminum
    • Brass
    • Bronze
    • Sandstone
    • Green
  • Units are recommended for indoor installation only, shielded from direct weather conditions.
  • Doors and trim are striated to resist scratching


  • Individual compartment size is 5 ½ in. W x 16 ¼ in. H x 6 ¾in. D
  • Doors include a 5 pin cylinder cam lock with 2 keys (1,000 different key changes)
  • Each door has a 2 ½ in. W x ⅝in. H indentation to accommodate a label (included) to identify the tenant's name and/or box number
  • Access door is designed to accept a USPS arrow lock (supplied and installed by your local Postmaster) or a private master lock (purchased separately)
  • Can be stacked two units high to save space

Mounting Options

Surface Mounted

  • Mounts directly to a surface and is attached with mounting hardware (not included) through the back

Recess Mounted

  • Fits into a rough opening and secured with mounting hardware (not included) through the back or side panels
  • Rough opening for recessed mounted vertical mailboxes is 1½ in. less than the unit's width, 1 ¼ in. less than the unit's height and equal to the unit's depth
  • Units include a fully integrated flanged collar which fits over the rough opening

Additional Options

  • Custom engraved, self-adhesive placards for door identification
  • Outgoing Mail Slot measuring 4 ¾ in. W x ½ in. H (in the far left door of the unit unless otherwise specified) *Order unit with one additional compartment than the total number of tenants receiving mail.
  • Matching Letter Boxes with optional custom engraving (example: "Rent Box" or "Outgoing Mail" in regular or black filled)
  • Factory installed Master Commercial Lock (for private access) with 2 keys
  • Replacement locks
  • Replacement doors
  • Additional keys
  • Key blanks (box of 50)

Installation Info

  1. Follow the included instructions for surface mounted or recessed mounted units. Installation hardware is not included with your mailbox purchase.
  2. The USPS will provide and install its own master lock on your mailbox unit; therefore, after installing the mailboxes, contact your local Postmaster for installation. The hardware and instructions for installing the master lock are included in your packaging. Please provide the hardware and instructions to the USPS representative when they arrive to install the lock.
  3. If for private use, purchase the Master Commercial Lock with your mailbox and it will arrive installed by the factory.


  • No more than two tiers of mailboxes may be installed.
  • For recessed units, the wall opening and lumber frame must be square.
  • Mailboxes should be shielded from direct weather conditions. These units are recommended for indoor installation only.
  • Store keys in a safe place until ready for use.
  • Hardware is not included to fasten units into rough opening.

Security Info

The tenant door at or near the center of the compartment array (door marked "U.S. Mail), in addition to providing access to a tenant's mail, also provides access to the USPS Arrow Lock that provides access to all compartments. For the sake of security of the entire compartment array, it is important that this tenant door is securely locked at all times, even if there is no tenant receiving mail via this door.

16 Door CBU

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16 Door CBU
For Your Reference:

OUR SKU is Salsbury Industries 3504BSU

This item is also sometimes listed under the following manufacturer numbers:

Dimensions & Weight
Ship Weight:
Salsbury 3504BSU 4 Door Vertical Mailbox Brass Finish Surface Mounted USPS Access
24.25 in. W x 19 in. H x 7.5 in. D
30.00 lbs
General Category:
Commercial Mailbox
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Frequently Asked Questions

Salsbury 3504BSU 4 Door Vertical Mailbox Brass Finish Surface Mounted USPS Access
Shipping Information:

Shipping Estimate:

Usually ships in 1 to 3 business days
Custom Engrave ships in 1 to 2 week

Stock Status:

In Stock

Ships to:

Ship Method:

FedEx/UPS (Learn More)

Shipping Policy:

Return Policy:

Return Instructions:

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Regarding a Product's Shipping Estimate

Understanding Lead Times

The lead times listed on this product page represent the best-case scenario for shipping estimates. While we may show that a product "usually ships" within a given period, this period should not be confused with a delivery estimate. Rather, we expect the product to ship from the manufacturer's warehouse within this time-frame.

What does this mean for you? Once you place an order on our site, we begin processing the order with the manufacturer. The processing lead time we list on the product page is the most current estimate from the manufacturer regarding the product.

Below, we answer the top three FAQs our customers have regarding delivery estimates.


How long will it take to receive my commercial mailbox?

When you order a commercial or cluster mailbox, we process the order with the manufacturer within 1 business day. Once processed, the order usually ships in the time-frame listed on the product page. Since Cluster Mailboxes are large items, they ship via freight carriers. This means that the transit times for these will usually be 5 to 7 business days.

A few things to note about purchasing a cluster mailbox or similar large, commercial-grade product:

  • The freight carrier will call the number you list on the shipping address a day before delivery to schedule a delivery appointment with you.
  • The manufacturer ships using their chosen freight carrier depending on the products ordered and the delivery location.
  • The majority of online retailers who sell commercial mailboxes (CBUs, etc.) ship directly from the manufacturers, just as we do.
  • If you purchase a commercial mailbox from us and decide to cancel because a competitor lists a "faster" lead time on their site, you may be delaying the time it will take to receive your mailboxes. Why? Because you are placing a new order to be sent to the same manufacturer for processing.
  • If you choose professional mailbox installation with your commercial mailbox purchase, please note that same-day installation is not available. Installation will be scheduled after the delivery of your mailbox. In most cases, installation is completed within one week following delivery.

What if I order multiple products from different brands?

If you ordered multiple products, it is possible that they are made by different manufacturers. If this is the case, your products will ship to you separately from each manufacturer.

For example, if you purchase a Mayne Post with a Whitehall Mailbox, your post will ship from Mayne's warehouse in about 3 business days, but your mailbox will ship separately from Whitehall in about 2 to 3 weeks if customized with address numbers.

How can I estimate my shipment's transit time?

Depending on the carrier and your location, transit times will vary. Delivery estimates are best projected using your carrier tracking number. Once your order ships, we'll send you a shipping confirmation email that includes your carrier (FedEx, UPS, YRC, etc.) and tracking number.

Note: If you place an order with us and do not receive an Order Confirmation email, check your spam inbox. If you still do not see an Order Confirmation email in your inbox, contact us right away at (866) 707-0008 . We will provide you with your Order Number and any other details you need.

What is the CBU Price Match Guarantee?

Price Match

It's pretty simple. If you find this model* cluster mailbox on another online retail site for a lower price, including any shipping and taxes, then we will match that competitor's price.

Before we can match a competitor's price, please note:

  • We will need the exact URL of the product page in question. A screenshot of the competitor website will not suffice.
  • Some competitors hide their freight charges until you enter the checkout, so please keep this in mind.
  • If you are ordering multiple units, check our Volume Discount Pricing table (to the right of our sale price) to see if we're the better price for the quantity you need.

* By "model", we mean a CBU that has the same number of tenant doors and the same manufacturer specifications.

Wall Mount Mailboxes Locking Mailboxes Commercial Residential

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