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7.5″ wide Medium Locking Mailbox Insert


Medium size locking mailbox insert creates a locking compartment inside a standard common 8″ wide mailbox.  These are not vaults, but they do protect mail from a casual thief and it offers an excellent visual deterrent. Once a mail thief sees your lockbox, hopefully they move on to an easier victim.

Move down for more info.  Click the TABS for info regarding USPS approvals and installation options.

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7.5″ wide medium size Locking Mailbox Insert –

We sell different size locking mailbox inserts.  This page is for the 7.5″ wide size unit that is sold to customers with a mailbox that has an opening that is at least 7.5″ wide (left to right).

  • Locking mailbox inserts add a locking compartment to an ordinary standard medium size mailbox.
  • Sturdy construction with 14 gauge steel doors and 16 gauge steel bodies with stainless steel hinges.
  • Four high security keys included.
  • Mail gets pushed through slot.
  • Slot bent inward to restrict a hand from reaching in to easily steal your mail.

These are not vaults, but they do protect mail from a casual thief and it will offer an excellent visual deterrent. Once a mail thief sees your lockbox, hopefully they move on to an easier victim.

Dimensions:   7.5″ wide size Locking Mailbox Insert

Measures approx 7.5″ wide x 5.75″ tall x 18.5 ” deep
Mail Delivery Slot size: 7.25″ wide x 1.5″ tall

Your mailbox opening must be at least 7.5″ wide (L-R)

Shipping to the 48 States:
Choose between FREE SHIPPING with deliveries usually 6-10 business days*… or the FASTER SHIPPING with deliveries usually in 1-5 business days*. (*Depending on your proximity to NY).

AK & HI deliveries…. add $20.00/lockbox


USPS Approvals

A locking mailbox insert (or lockbox) is an accessory to a mailbox and accessories do not receive specific approval or denial.  Only the mailbox itself receives universal USPS approvals.

Whether a lockbox can be used or not is entirely up to your local Post Office. In almost all cases, since mailbox lockboxes have been around for so many years, even the smallest lockbox is “OK” with the local USPS…. simply because mail-theft is not only a homeowner problem, it’s also a problem for the USPS.

Most local postmasters allow lockboxes simply because it cuts down on the mail theft problems they need to deal with…. but… problems can occur when local USPS people (whether it be the postmaster or the letter carrier himself) object to the use of a lockbox. In that event, they’ll stop your mail until the lockbox is removed.

If you have mail theft concerns, and think a lockbox might resolve your problem, I would ask your letter carrier for permission to use the lockbox. Chances are there are other lockboxes in your neighborhood. You can also speak with someone at your local post office and if they say yes… then you will not have any unexpected problem.

It is very important to explain that only letters go through the slot into the lockbox.  Sometimes the USPS people think you want all the mail hand-fed through the delivery slot. Actually, you only need the letters to be secured.  Junk mail and larger items get placed in the unsecured area on top of the lockbox.

Standard Installations

Our locking mailbox inserts are fairly easy to install.  They get bolted to the mailbox floor.  We include the stainless steel mounting bolt with a matching lock nut.  Our locknut looks like a regular nut, except it has a vinyl threaded core.  Once the bolt and nut are tightened together, the vinyl threads make it impossible for someone to simply back-off the nut.  The vinyl grabs the threads of the bolt so tightly, any attempt to back-off the nut will result in the bolt/nut just spinning and spinning.  The only way to back-off the nut would be if you have a key to open the locking insert door, and hold the bolt head from turning.
Once you’ve placed the locking insert inside the mailbox and confirmed they fit well together, you’ll need to drill a 3/8″ hole in the mailbox floor to coincide with the hole in the locking insert hinge assembly.  Be sure that the insert is centered perfectly to avoid any possibility of the locking mailbox insert door from scraping against the side wall of the mailbox opening.  You can always fine-tune the mounting hole location using a “rat-tail” file.  Your goal is the have the locking insert mounted perfectly in the center of the mailbox opening.
Once the hole in the mailbox floor is completed, simply bolt the locking insert in place using the aforementioned bolt/locknut.  Tighten just until snug.  No need to clamp down and over-tighten.
​And…  that’s it.  Your incoming mail has just become more secured.

Column Installation

Column Installations:


We provide a bolt for attaching to the mailbox floor. If the mailbox floor has about 1.5″ protruding out from the brick, you can use the bolt we provide.

If not, then there is a brick in the way directly under the front/bottom of the mailbox and that will require a higher level of handiness. You would need to pick up locally the hardware needed to make the attachment into that brick.

That type of attachment would involve drilling a hole down into the brick that is just under the front of the mailbox floor using the hole in the lockbox hinge as a guide.

Once the hole is drilled down into that brick, you will most likely insert a “molly” plug into that hole… and use the matching screw to fasten the lockbox in place.

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