When you have multiple tenants to consider, choosing the safest and most durable mailbox system is important. Our 4B and 4C horizontal mailbox styles, made by Salsbury Industries and Florence Mailboxes, come in a number of configurations and customizable options without sacrificing a bit of security and dependability. Compare and contrast the two here to find your perfect fit!

Approved for

  1. New construction Private Use* only

  2. Replacing old 4B mailbox units of the exact same overall unit size

Approved for

  1. All types of new construction effective Oct. 2006

  2. Replacing old 4B mailbox units where USPS delivery is required

  3. Replacing old 4B mailbox units where the overall unit size has changed

Rated for Indoor Use Only

Rated for Indoor and Outdoor Use

Front or Rear Loading

Front or Rear Loading

Recessed Mounted

Recessed Mounted

Surface Mounted (front-loading, single or double-wide units only)

Free-standing Depot (front-loading only)

Pedestal Kiosk (Private Use* only)

Cube style Compartments

5”h x 6”w OR 5”h x 12½”w

Rectangular style Compartments

3”h x 12”w x 15”d OR 4 ¾”h x 12”w x 15”d

Tenant Cam Locks w/ 2 keys

Tenant Cam Locks w/ 3 keys

Master Locks

  1. USPS-installed master Arrow lock ready

  2. Private master lock

  3. Private Use* only combination lock

Master Locks

  1. USPS master Arrow lock ready for front-loading units

  2. No locking mechanism for rear-loading units, therefore secure mailroom is required

Aluminum w/ Stainless steel locks & hinges

Aluminum w/ Stainless steel locks & hinges

Finishes: Aluminum, Dark Bronze, Gold Speck, Sandstone (finish options may vary per unit)

Finishes: Aluminum, Dark Bronze, Gold Speck, Sandstone, Black, White, Antique Bronze, Silver Speck, Postal Gray, Forest Green (finish options may vary per unit)

Parcel Lockers

  1. No ratio requirements

  2. 10⅜”h x 12⅞” w OR 15¾”h x 12⅞”w

  3. Integrated

Parcel Lockers

  1. Min. of 1 locker per 10 Compartments

  2. 19 ¾”h x 17 ½”w OR 23 ¼”h x 17 ½”w

  3. Integrated or Stand-alone

Outgoing Mail Unit

  1. Optional access lock

  2. Integrated on some configurations

Outgoing Mail Unit

  1. Anti-fish comb & protective hood

  2. Integrated on all configurations

Door IDs

  1. Standard clear plastic card holders ⅝”h x 2”w

  2. Self-adhesive ID numbers 1-3000 upon request w/ no extra charge

  3. Custom engraved numbers in the USPS Standard US Block font ⅜”h, max 12 characters per line, max 2 lines per door

Door IDs

  1. Standard silver adhesive decals w/ black font 1 ½”h x 1 ¾”w, max 5 characters per decal

  2. Custom engraved numbers in the USPS Standard US Block font ⅜”h, max 12 characters per line, max 2 lines per door

    1. Black or White color fill options

    2. Other customization may be available

Door ID Layout

  1. Standard numbering from the top down, left to right

  2. Custom layouts available via the Custom Layout Form

Door ID Layout

  1. Standard numbering from the top down, left to right

  2. Custom layouts available

Available in Standard Clusters of

  1. 1-10 tenants

  2. 11-20 tenants

  3. 21-30 tenants

  4. 30+ tenants

  5. Further customization available upon request

Available in Standard Clusters of

  1. 3-15 compartments high

  2. Max height is 56½”

  3. Further customization available upon request

Other Accessories

  1. Collection boxes

Other Accessories

  1. Wall mount trash & recycling bins

  2. Letterboxes for USPS delivery

  3. Key keepers for USPS delivery

  4. Collection boxes

  5. Directories

May not meet ADA requirements

Meets ADA requirements

Part Replacements Available

Part Replacements Available


*Private Use only: Office building, apartment complex, college, etc. where a USPS worker delivers mail to one central location. A building employee then distributes the mail to each tenant's compartment.

Choosing the best horizontal mailbox unit for your building is as important to us as it is to you. Please feel free to contact us with any questions or for help choosing between our 4B and 4C unit options.