Double Barn Door Underbody Box

The toughest and most reliable double door boxes on the open road.

The HPI Double Barn Door Underbody Box has doors that will never sag and don't need bungee cords to keep them closed. We have seen many times where the trailer has been high-centered on railroad tracks, dragging the underbody tool boxes, and actually lifting the trailer off the ground while dragging. Afterwards, only minimal damage to the bottom of the Highway Products underbody tool boxes. The doors still worked fine. We've seen situations where the trailer was dropped, fully loaded, without the landing gear down. The boxes took the full force. Minimal damage to the underbody tool boxes and the doors still worked fine. These boxes are built to last forever. Call us today and lock in your box game for decades to come!

Like our Double Barn Door Underbody Box but want something special done to it? Call our sales team now to start creating your own custom variant!

HPI Benefits

The HPI difference is in the materials we use, the attention to all details and ultimately products we produce and proudly guarantee. Our promise is to take the best care of your product while we manufacture it, and continue to care for a lifetime after you receive it.

Lifetime Warranty

All of our products come with a Lifetime Warranty against defects in manufacturing (failed welds, etc.). It also includes all locking mechanisms, hinges, gas shocks, weatherstripping and any other materials we use. Learn More

Military Grade Aluminum

Highway Products uses nothing but the best materials. Our products are hand crafted out of Military Grade aluminum. Why take it that far? The days of using nothing but the best ingredients are all but gone in this world. We refuse to sink to that level. That’s the HPI difference.

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Hand-Made in the USA

Hand crafted from beginning to end right here in the USA. Every square inch of our products are touched by human hands, every step of the way.

This product can expose you to chemicals that are known to the State of California to cause cancer. For more information, go to

Product Features

All HPI products come standard with options and features that you would normally pay extra for. Please explore all of our standard and optional features and call us with any questions you may have!

  • 5052 Smooth Aluminum
    We build our Double Barn Door Underbody Box from rust-free 5052 aluminum, the same material used by the military, aircraft manufactures and boat builders.
  • T Handle Locks
    Our ergonomically designed T-Handle locks are the most secure locking mechanism on the market.
  • Piano Hinges
    Piano hinges provide full-length support and reduces stress points caused by inferior hinges.
  • Reinforced Strength
    Highway Products tool boxes are reinforced and reinforced again. That's why they last for millions of miles. We didn't get our reputation from skimping. Our underbody boxes are built with Herculean strength.
  • Stainless Steel Torx Screws
    Stainless steel Torx screws are the toughest fasteners on the market today. These fasteners won't loosen as you drive down the road and a door can be replaced without a special rivet gun.
  • Angle Bracing
    One of the weak points of truck tool boxes is the bottom corners. There is so much road stress from carrying heavy tarps, chains, tools, and other equipment, the corners sometimes break. Highway Products has eliminated this problem with reinforced angle bracing welded in the corners.
  • Spring Loaded Locking Rods
    Road vibrations may rattle doors open allowing expensive tie-down equipment or tools to fall out on the highway. Highway Products spring-loaded locking rods keep the doors from opening. In fact, the more vibration you get, the more they try to close.

    Note: This feature available on some models, depending on door size.
  • Firefighters need boxes for clothing, extra nozzles, hoses and hydrant wrenches. And contractors use them on a variety of service vehicles for tools and supplies.
  • Optional Dividers
    A divider option placed on one side of the underbody tool box keeps tie-down chains from drifting around the tool box, plus a hanging bar.
  • For additional security to protect your valuable cargo, an additional feature that can be added is our Security Bar Lock. This complete tool box bar lock style door lock for semi-truck double barn door underbody boxes can also be purchased separately for applications such as trailer doors, storage sheds, job site sheds or job boxes.

Double Barn Door Underbody Box Videos

Double Barn Door Underbody Box Images

Hpi Black Diamond Plate

HPI Black Diamond Plate

Our signature HPI Black Diamond Plate finish combines that trendy satin look with just a little shine to hide scratches and keep that tough black look.

Diamond Plate

Diamond Plate

Tried and true. The all time classic finish. Rugged, durable and will last forever.

Hpi Black

HPI Black

Our signature HPI Black finish combines that trendy flat look with just a little shine to hide scratches and keep that tough black look.


Custom Colors

Custom colors? You bet we do that! Whether you need a color match, want something to stand out or blend in, we can cover it.

Interested in our Double Barn Door Underbody Box?

Our team of Product Specialists are on standby to answer any remaining questions you have about our Double Barn Door Underbody Box or to assist you in placing your order.

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