Hidden Mailbox Key Holder (Magnetic)

Keep a spare key exactly where you’ll need it—inside your mailbox—without it being visible from the outside.

There are now 5 different option available for any taste and need:

Print Profile 1 Print Profile 2 Print Profile 3 Print Profile 4

Option 1

This Option is the most simple , just a container

Option 2

This option has a clip that holds key form falling out

Option 3

This option has more space inside and uses less filament

Option 4

This option has a side grip so it is easier to grip the container by it's sides in a small space

Option 5

This option has a sliding guard with a handle, it's ease to slide it in and out to protect the key form falling out

What it is
A slim, 3D-printed magnetic holder that mounts to the inside wall or ceiling of a metal post box. From outside you can't even see it , unless you know it is there.

Why
For those “locked out” moments, this gives you a discreet backup that lives in your post box, not under a doormat.

How it works

• Magnets sit on the back/outer side of the holder so they directly touch the metal wall for maximum grip.
• Mount on a side wall or the top wall (ceiling) of the mailbox.

Hardware / BOM

• 4× round magnets Ø6×2 mm (use your preferred size; scale pockets if needed)

Here highlighted in blue - you can see where magnets need to be inserted.

• Optional: tiny foam dot/tape to prevent rattle
• Adhesive: CA gel or 2-part epoxy for magnets (check polarity before gluing!)

Assembly

• Press-fit or glue magnets into the rear pockets so they will touch the metal wall when installed.
• Test magnetic pull on your mailbox surface.
• Insert key;
• Stick the holder inside the mailbox (side or top) where yo can reach it. with your hand when mailbox is closed

Notes & safety

• This is a convenience holder, not a high-security safe. Keep the mailbox locked.
• Check local rules for storing items inside a postal box.