Built Like a Vault—Now with the Most Room

Think Fortified Safe Security—for your mail and packages. With the Vault XXXL, you can trust your deliveries are protected.

The Vault XXXL is 6″ wider than the Vault XXL, giving you the largest capacity in the series while maintaining the same uncompromising Fort Knox construction: ¼” solid steel, hand-welded seams, incoming mail baffle, recessed doors, and zero pry points.

It’s maximum space with maximum security—backed by the same legendary Fort Knox protection.

Built for Maximum Security

• Size: 24” W × 36” H × 24” D
• Weight: 400 lbs of solid steel construction
• Package Capacity: fits boxes up to 6” H × 22” W × 10” D
• ¼″ thick steel body
• 3/16″ reinforced steel doors
• Seamless hand-welded construction (no rivets, no weak points)
• Oversized 2″ continuous welded steel hinge
• Includes Vault Lock Extreme with Medeco® lock + 2 keys
• Brushed satin nickel pull handle
• Powder-coated inside & out for weather protection

Custom Sizes Available → Call 1-800-206-8067 or email custom@fortknoxmailbox.com

Why Customers Love the Vault Series

• Available in four sizes
• Stores large volumes of mail and packages in one secure compartment
• No need to unlock multiple doors every day
• Perfect for travelers, snowbirds, and long-term storage needs
• Go days or weeks without checking in, worry-free

Need something unique? We also build custom sizes—contact us to get started.

✅ Meets all USPS requirements

How It Works

Simple. Secure. Built Like a Tank.

1. Carrier pulls down the handle and the baffle raises inside.
2. Mail carrier inserts mail and packages into the baffled door area and closes.
3. Mail or small packages drop into the baffle door.
4. As the door closes, items fall into the locked compartment below.
5. Only you have the key—peace of mind every day.

Mounting Made Simple

The Vault XXXL is pre-drilled with 8 holes (6 ¾” apart) and ready to install:

• In-Ground T-Post: 5" × 23" × 50" (for XL, XXL, and XXXL Vaults)
• Surface Mount T-Posts: 5" × 24" × 18" (for sidewalks, driveways, or hard surfaces)
• Can also be set into masonry for a built-in look

Style & Options

• Standard colors: Slate Gray or Glossy Black
• Upgrade: any custom solid powder coat color (See color chart HERE)
• Free 1¾″ adhesive address numbers included
• 3" Side numbers available
  

Extra Upgrades Available

• Outgoing Mail Slot + Flag (1½″ slot inside box)
• Rear Door Access (front & rear keyed alike, or welded/sealed front)
• Mounting choices: In-Ground or Surface-Mount (breakaway) T-post
  
• Motion-activated LED light

In Short

The Vault XXXL is designed for the biggest deliveries and maximum peace of mind. At 325 lbs of solid steel, with a lock system trusted by security professionals, it’s not just a mailbox—it’s a Garrison on your curb.