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4C Mailboxes USPS Approved

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Colors Available:
aluminium aluminium
bronze bronze
sandstone sandstone
black black

Required for new construction and major renovations, 4C horizontal mailboxes are ideal for commercial buildings, multi-family housing units, apartment complexes, government and military bases, schools, colleges and other residential and commercial developments. Salsbury Industries manufactures USPS STD-4C Horizontal mailboxes that are required for new construction and/or major renovations.  4C mailboxes are made of heavy duty aluminum and stainless steel hardware and come available in configurations that are 1 door wide (single column) and 2 doors wide (double column).   

 
 

4C Mailboxes are a Great Choice for Many Applications 

Salsbury 4C mailboxes are ultra-durable and come in various sizes and color options. Configurations vary in the number of mailbox doors and parcel lockers to help accommodate your community size and the number of mailboxes needed. They also make receiving packages simple. Our USPS approved 4C mailboxes are very secure with built-in heavy duty cam locks for added security and anti-fish plates to prevent tampering.

 

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4C Recessed Mounted Mailboxes

The Salsbury recessed mounted 4C horizontal mailboxes and parcel lockers are U.S.P.S. approved and come in 4 different heights – 6 door high, 10 door high , 11 door high and Maximum Height units. 4C recessed mounted mailboxes are available with front and rear loading compartments and can be used for indoor and/or outdoor centralized mail delivery. Each unit includes a compartment for outgoing mail collection and is labeled “Outgoing Mail.” The outgoing mail compartment includes a weather protection flap and mail slot. The United States Postal Service requires every 4C Mailbox configuration to have 1 parcel locker for every 5 mailbox doors. All Salsbury 4C mailboxes come with a 5 year warranty and are available in aluminum, black, bronze and sandstone.

 
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4C Surface Mounted Mailboxes

The Salsbury surface mounted 4C mailboxes are accessed from the front through one or two (2) easy opening master door panels. 4C Surface Mounted Horizontal Mailboxes include a U.S.P.S. approved 4C mailbox with a matching surface mounted enclosure. Each unit includes a compartment for outgoing mail collection that is labeled “Outgoing Mail.” The outgoing mail compartment includes a weather protection flap and a mail slot. 4C surface mounted mailboxes can be used for indoor and/or outdoor centralized mail delivery and are available in aluminum, black, bronze and sandstone. The United States Postal Service requires 4C mailboxes have 1 parcel locker for every 5 mailbox doors. All Salsbury 4C mailboxes come with a 5 year warranty and most orders ship within 5 to 7 business days. 

 
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4C Free-Standing Mailboxes

Used for indoor and outdoor centralized mail delivery, the 4C free-standing mailbox includes a U.S.P.S. approved 4C mailbox with a matching free-standing enclosure. The 4C free-standing mailbox is easy to assemble and features a durable powder coated finish available in aluminum, black, bronze and sandstone. Each unit includes a compartment for outgoing mail collection that is labeled “Outgoing Mail” and the outgoing mail compartment includes a weather protection flap and a mail slot. All Salsbury 4C mailboxes come with a 5 year warranty and most orders ship within 5 to 7 business days. The U.S.P.S. requires a minimum of 1 parcel locker for every 5 tenant compartments. Free-standing 4C mailboxes provide a convenient means of installing 4C mailboxes in locations where a wall mounted application is not desired or available.

 

USPS Approved 4C Mailboxes

STD-4C Horizontal mailboxes are USPS approved and commonly used in apartment complexes, commercial buildings, residential developments, condominiums and several other applications. When you set up your 4C mailbox, the local post office will install an “Arrow Lock.” This lock is used for the local post master to open the unit and deliver the mail. When the U.S. Postal Service delivers a package to the parcel locker, a parcel locker key is placed in the recipient’s mailbox. Once the recipient opens the parcel locker, the key is automatically retained in the lock until it is removed with the USPS control key. 

 
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Mailbox Configurator

Design a Mailbox Configuration - Our Mailbox Configurator will help you determine the optimal number of mailboxes and parcel lockers needed on your specific requirements. A summary with elevations, rough opening dimensions, sample installation instructions, model numbers, and other useful information is provided.

 

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More Info About 4C Horizontal Mailboxes

Salsbury horizontal style commercial mailboxes are ideal for apartments, condominiums, office buildings, military bases and residential developments. Made entirely of aluminum, 3700 series 4C horizontal mailboxes are U.S.P.S. approved and available as front loading units or rear loading units. Salsbury 3700 series 4C horizontal mailboxes and parcel lockers meet the specifications of USPS-STD-4C. The 4C horizontal mailboxes are required for new construction and/or major renovations effective October 2006.  

 

Additional Resources

4C Horizontal Mailboxes Questions

Questions & Answers

What is a 4C mailbox?

USPS STD-4C horizontal mailboxes are centralized, wall-mounted mailboxes that are required for new construction and major renovations. A “major renovation” occurs when the wall where the existing mailboxes are installed is being significantly modified.

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What types of 4C mailboxes are there?

Salsbury Industries carries recessed mounted 4C horizontal mailboxes and parcel lockers, surface mounted 4C horizontal mailboxes, and 4C free standing mailboxes.

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What are the 4C mailbox requirements?

The USPS-4C Standard includes the following specifications:

  • A minimum size requirement for mailboxes (12” W x 3” H x 15” D).
  • A parcel locker requirement based on a 1:5 parcel locker to mail compartment ratio (effective July 2020).
  • Strengthened security requirements for 4C units.
  • Standardizes and improves tenant compartment lock design.
  • Adds testing requirements to verify acceptability for either indoor or outdoor use.

For more information, visit our United States Postal Service Mailbox Regulations and Specifications page.

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What’s the difference between 4C and 4B+ mailboxes?

USPS STD-4C horizontal mailboxes are designed for higher security and required for new construction and major renovations, while only 4B horizontal and vertical mailboxes are for direct one-to-one replacements. 4B horizontal and vertical mailboxes are permitted for replacement use if no changes to the rough opening where the existing wall-mounted mailboxes are currently installed (though you should always check with your local Post Office to be sure). If that isn’t the case, 4C mailboxes must be used.

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Are 4C mailboxes easy to install?

You can find clear and easy-to-follow instructions as well as helpful 4C videos for all Salsbury Industries 4C mailboxes on our website—just scroll to the bottom of the individual product pages. You can also visit our Video Library.

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What are the benefits of 4C mailboxes?

4C Horizontal mailboxes are ideal for indoor and outdoor use and are extremely durable. They come in a variety of sizes and four contemporary colors, aluminum, bronze, sandstone, and black. The number of compartments and parcel lockers vary, so you will be able to find the perfect mailbox for your building.

These mailboxes include an outgoing mail slot with an anti-fish plate, heavy-duty cam locks for each tenant door with three keys, spacious compartments, and secure parcel lockers.

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Who is responsible for 4C mailboxes?

According to USPS regulations, the property owners, builders, or developers are responsible for 4C mailboxes. The USPS’s Postal Operations Manual states, “Purchase, installation, and maintenance of mail receptacles are the responsibility of the customer.”

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Where to buy 4C mailboxes?

Salsbury Industries manufactures a wide variety of durable, heavy-duty USPS STD-4C Horizontal mailboxes that are required for new construction and/or major renovations. Check out all the 4C mailboxes we offer here.

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Are 4C mailboxes weatherproof?

Salsbury 4C mailboxes are made of heavy-duty aluminum and stainless steel hardware and feature a durable powder coated finish that will stand up well to harsh weather conditions. The outgoing mail compartment also includes a weather protection flap.

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What is centralized mail delivery?

Centralized mail delivery is a mail delivery system in which the mail carrier delivers mail for multiple residences at one central location.

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Do 4C mailboxes meet ADA guidelines?

Salsbury Industries’ 4C mailboxes include mailboxes and parcel lockers that fall within ADA height requirements.

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What are parcel lockers?

A parcel locker is a lockable compartment designed to hold packages that will not fit in a standard mailbox compartment.

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How do parcel lockers work on 4C mailboxes?

When a mail carrier is unable to fit a package into a standard mailbox compartment, they will place your package in a parcel locker. The carrier will then leave the key to the parcel locker in your mailbox. (If you look up the USPS tracking number for your package online, you will see a message like “Delivered to Parcel Locker” when your delivery arrives.) To get your package out of the parcel locker, you simply need to use the key the mail carrier has left in your mailbox to unlock the parcel locker. The key will have a tag that indicates which locker contains your package. Once you have unlocked the parcel locker and retrieved your package, the key capture system will secure the parcel locker key in place so that it can’t be removed. Only a USPS mail carrier will be able to remove the key with a master key. If you’re still unsure of how parcel lockers work, consult this helpful video.

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How big are 4C mailbox doors?

Salsbury 4C mailbox doors come in four sizes. MB1 doors are 3-1/4” H x 12-3/4” W, MB2 doors are 6-3/4” H x 12-3/4” W, MB3 doors are 10-1/4” H x 12-3/4” W and MB4 doors are 13-3/4” H x 12-3/4” W.

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How many parcel lockers are needed with 4C mailboxes?

Effective July 2020, the USPS-4C Standard includes a parcel locker requirement based on a 1:5 parcel locker to customer compartment ratio. This means that there should be at least one (1) parcel locker for every five (5) mailbox compartments.

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Can I customize a 4C mailbox?

Salsbury 4C Custom Horizontal Mailboxes and parcel lockers are available as recessed mounted, surface mounted, and free standing units in configurations that are one door wide (single column) and two (2) doors wide (double column). Units can be configured with a combination of four (4) mailbox door sizes and five (5) parcel locker door sizes to meet your custom requirements. Click here to view more detailed information about Custom 4C Horizontal Mailboxes. Other customizable options available for all Salsbury 4C mailboxes include custom colors, custom engraved placards and custom engraved doors (regular or black filled).

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What is a 4C mailbox configurator?

Salsbury Industries’ 4C Mailbox Configurator will help you determine the optimal number of mailboxes and parcel lockers needed based on your specific requirements. The 4C Mailbox Configurator provides a summary with elevations, rough opening dimensions, sample installation instructions, model numbers, and other helpful information. All 4C horizontal mailbox styles can be configured. To customize your unit, access our 4C mailbox configurator here.

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