4C Mailboxes from Postal Products Unlimited in Milwaukee, WI

Postal Products Unlimited manufactures several types of 4C Mailboxes - Choose the perfect system for your project:

3 Door Mailbox
16 Doors w/2 Parcel Lockers
4C Mailbox CAD Drawings

4 Door Mailbox
8 Doors w/Parcel Locker
Intallation Instructions - PDF

5 Door Mailbox
View 4C Internal Images

7 Door Mailbox
1P 4C Parcel Locker

9 Door Mailbox
2P 4C Parcel Locker

Reduce identity theft with the highest security mailbox on the market

When Security is A Must! The new 4C Mailboxes are built with features that promote mail security. Check out some of the key improvements below:
Protective Lock Rim to prevent twisting and torque on the lock
Protective Lock Rim to prevent twisting and torque on the lock
3-Point Lock Cam secures the door in 4 places including the hinge side.
3-Point Lock Cam secures the door in 4 places including the hinge side.
Smaller Carrier Access Door provides smaller pry points and increased overall strength.
Smaller Carrier Access Door provides smaller pry points and increased overall strength.

4C Mailbox Product Features:
  • USPS Approved
  • Made from a high strength and stainless steel
  • Flush surface design and concealed hinges
  • Tampering and prying open doors is close to impossible
  • Double-wall door design increases pull test capacity
  • Closer tolerances of each box reduces the size of pry points
  • Units feature a 3-point cam lock with protective lock rim
  • Door secures in four places including hinge side
  • Each unit comes with an outgoing mail slot and carrier access door
  • Outgoing mail slot features a saw tooth guard
    to prevent mail from being fished out
  • Available Options: size, door count, custom colors (minimums apply)
  • Installation is easy! 4C Mailboxes quickly install between wall studs
  • Recommended for Indoor Use Only

4C Horizontal Mailbox Applications Include:
  • Residential Builings
  • Multi-Family Residences
  • Centralized Mail Delivery Locations
  • Industrial Complexes
  • High Security Locations
  • Private Delivery Dorms
  • Office Mail Rooms
  • Parcel Delivery Locations
  • Private Postal Centers
  • Government Agencies
  • K-12 Schools
  • Financial Institutions
  • Military Bases
  • Medical Facilities
  • Colleges and Universities
  • Apartment Complexes and Condos

Postal Products Unlimited, Inc. is first to manufacture the USPS approved Standard 4C Horizontal Mailboxes – primarily to be used in apartment complexes, commercial buildings and multi-family homes. In cooperation with the USPS and a National Consensus Committee, we have designed the 4C mailbox to meet today’s consumer mailing habits, as well as provide increased security.

As of October 6, 2006, the 4C Horizontal Mailbox will be mandatory on any new construction projects. Arrow locks are only allowed to be installed on units that meet the current specifications. Please call us for assistance with drawings or choosing the appropriate 4C mailbox for future projects. 4C Mailbox CAD files are available to download. Click here

The 4C Mailbox System is Recommended for Indoor Use Only.
Interested in USPS approved outdoor mailbox systems? Find out more about Cluster Box Units.