3621 – 4B+ Horizontal Mailbox – 7 Door High Unit -21 Doors (20 Usable) – Front Loading – USPS Access


4B Horizontal Mailboxes are USPS approved for replacement installations. All units are available in front- loading or rear-loading configurations with options for 10 – 35 tenant doors.

Original price was: $2,140.00.Current price is: $2,076.00.

Item#: 3621F



SAVE $64 (Reg. $2,140)


Contact Us for Bulk Pricing

In Stock
Ships in 5 days

Found a lower price? We will beat it!

Product Description

Salsbury 3600 Series 4B+ Horizontal Mailboxes – Front Loading – U.S.P.S. Access


Size: 29.25″ W x 40.75″ H x 16.5″ D

Weight: 85 lbs.




  • 4B+ horizontal mailboxes are U.S.P.S. approved for replacement and/or retrofit installations
  • Manufactured by Salsbury Industries to USPS-STD-4B+ Specifications
  • Ideal for apartments, condominiums, commercial buildings and residential developments
  • Made entirely of aluminum
  • Feature a durable powder coated finish available in aluminum, bronze, gold and sandstone
  • Available in “A” size doors (6-1/2″ W x 5-1/4″ H) and larger “B” size doors (13″ W x 5-1/4″ H)
  • Units with standard “A” size doors are available in 3, 4 or 5 doors wide and 5, 6 or 7 doors high
  • Units with larger “B” size doors are available in 2 doors wide and 5, 6 or 7 doors high
  • Doors include a 5 pin cylinder cam lock (with 2 keys)
  • Front loading door panel swings on a continuous hinge
  • Rear Loading – All openings are usable on rear loading units.
  • Front Loading – One mailbox opening is required for a master postal lock (installed by the U.S.P.S.) and cannot be used for mail distribution
  • Rear Loading – Include factory installed 3/4″ W x 1/4″ D trim and a removable aluminum rear cover
  • Front Loading – Include factory installed 3/4″ W x 1/4″ D trim and a solid rear cover
  • Salsbury Industries is an ISO 9001: 2008 certified company and has excelled in the field of manufacturing since 1936



Why Shop Mailbox Emporium?


    • 5 Star Customer Service – At Mailbox Emporium, we strive to provide you with the best possible mailbox purchasing experience every time you shop with us. Check out our 5 star reviews and see why over 30,000 customers choose us for their mailbox needs. Have mailbox questions? No worries, we have the answers! Chat online or call one of our mailbox experts today.


    • Low Price Guarantee – Shop with confidence! We regularly check our competitors’ pricing to make sure we have the lowest prices online in the US. If you ever find a lower price from an authorized mailbox dealer, send it our way and we’ll beat it. Guaranteed!


    • Free & Fast Shipping – Yup, we offer that too. Free shipping is available on all products we sell in the continental United States. Many items are available to ship out in 2-3 business days.


    • Highest Quality Mailboxes – For commercial and community mailboxes, we sell only authorized Florence and Salsbury products. These two companies manufacture the highest quality mailboxes in the US and most products include a 5-year, worry free warranty. We are proud to sell American Made Mailboxes!


Call a Mailbox Specialist Today – 1-888-352-9194


Ron KY, United States
Great service and easy ordering


Charlie HNY, United States
Website was simple and easy to use, and customer service was so friendly and helpful with my questions. A great buying experience!

Tech Docs

tech_3621 – Technical Drawing (PDF)

inst_horizontals_front – Installation Instructions (PDF)


Salsbury Industries Warranty Information


Salsbury Industries provides a three (3) year limited warranty to the original purchaser. This three (3) year limited warranty is extended to five (5) years for the 3300 series Cluster Box Units (CBU’s), Regency® CBU’s and the 3400, 3700, 3800 and 3900 series 4C horizontal mailboxes. Salsbury Industries warranties cover defects in material and workmanship if reported in writing to Salsbury Industries within three (3) years (five (5) years for CBU’s and 4C) of the delivery date.


This warranty is limited to the cost of the products and does not include installation costs, transportation neglect or costs, misuse or alterations by the customer. Some states do not allow limitations on how long an implied warranty lasts or the exclusion or limitation of incidental or consequential damages; as such this limitation and exclusion may not apply to you. Salsbury Industries, at its option, may replace or repair defective products.