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Horizontal Apartment Mailbox: 900 Series
 (Recessed Installation)

Security's Horizontal Apartment Mailbox's are constructed of all aluminum extrusion and materials.  Standard 900 series horizontal mailboxes are available in "A" size compartments, 5" H x 6" W and configured in modules 3, 4, or 5 boxes wide and 5, 6, or 7 boxes high. Each ⅛" extruded aluminum door swings on a continuous hinge and is equipped with a 5-pin cylinder cam lock with 3 keys (1500 changes).

900 Series Features:

  • Doors include permanent " H engraved identification for a neat, uncluttered appearance.
  • Larger size boxes can be integrated into all modules for volume incoming mail as well as outgoing mail through a mail slot.
  • Package delivery can be accommodated with the addition of parcel boxes with a dual locking system. 
  • All modules have standard " integral trim for stability, easy installation and finished appearance when recessed into a wall opening.

Front Loading: Master door swings on a continuous hinge and features a top to bottom locking bar for security.  One compartment is required for postal access and cannot be used for mail delivery but with the addition of a mail slot in the door it becomes an outgoing letter box.  Postal access door is prepped to accept postal lock provided and installed by local postal authority.

Rear Loading: All compartments are usable for incoming mail. Lift-off or hinged rear covers are available.

Locks: 3 keys and 1500 key changes. 5- pin cam lock or with dust cover lock.

  • Combination spring latch lock must be approved by local postmaster for use in U.S. Postal Service Installation
  • High security all point locking system on door uses five pin cam lock.

Doors: U.S. Postal Service approved shall be fabricated from high strength aluminum with a minimum thickness of ⅛, max. of (must be specified), and swing on concealed hinges. The module is built with integral trim; no need for snap-on trim. This allows for stronger box and front loading main door to be precision fitted to preclude prying. Extruded aluminum (available in different sizes)

  • Hinged Doors: continuous to deter prying
  • Door Identification: 900 Series may have high number or letter permanently engraved in the face of door or aluminum or plastic tab. Numbering to be vertical, in sequence, starting from top to bottom. Numbering to be furnished to mailbox manufacturer by architect or owner
  • Option: Instead of engraving a 1 x 1 black lettered aluminum numbered tab for indent or a clear plastic windows

Master Frame: Precision fitted with integral trim to prevent sagging

Shelves: Riveted for added protection

 Available Options

  • Snap on trim instead of integral
  • Black lettering
  • Spring latch lock
  • Windows/Card holders
  • High security lock system
  • Combination lock
    (private use)
  • Special custom sizes available


  • Mail Slots
  • Keyed alike
    (private use)
  • Parcel lockers
  • 1/4" high security aluminum doors
  • Rear cover for rear load
  • Doors prepared for keyed-in cylinders
  • Private Use Options- Spring latch locks, Combination spring latch locks. Access doors keyed alike.

SMC Products
Cluster Box Units
4C & Horizontal
Postal Specialty
Private Mailbox
Secure Locking Mailbox
Vertical Mailbox

Request Quote

 Download Product Info

Download Horizontal Mailbox product brochure (401kb pdf)

Download 900 Series product brochure (124kb pdf)

Download 900 Installation Instructions
(82kb pdf)

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  Available Door Heights
  5-1/16" x 6
  127mm x 152
5-1/16" x 12 127mm x 318
10⅜" x 12
263mm x 318

15" x 12
400mm x 318


Selection Guide


anodized aluminum
anodized aluminum
bronze powder coat
powder coat
textured beige
gold powder finish
powder finish
silver powder coat
powder coat
hunter green

Clear anodized or baked on powder coating to offer chip and corrosion resistance

 Weight Chart


7H x 5W
7H x 4W
7H x 3W

83 lbs


6H x 5W
6H x 4W
6H x 3W



5H x 5W
5H x 4W
5H x 3W


 Door Identification

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  Security Manufacturing Corp.
   700 Freeport Pky Ste 300, Coppell, TX  75019 
   Tel: 800-POBOXES - (800-762-6937)