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Drop Door Semi Box

Drop Door Semi Box

keep your straps, tarps, and tools secure and accessible.

Drop Door Semi Box

Lifetime Warranty

Designed to last a million miles

  • Lifetime Warranty since 1980 = over-engineered and overbuilt
  • American Made by skilled tradesmen
  • Built with only premium materials and components
  • Sealed for protection from thieves and weather
  • Multiple finish options
  • Lifetime Warranty – Retire your truck but keep the box
Lifetime Warranty

The Highway Products Drop Door Box is the only underbody toolbox designed and built to last a million miles.  With structural corner gussets, angle braces, and bottom face stiffeners you can be sure that this underbody toolbox will not fail to the tests of the road.  Like everything else we build, the HPI Drop Door Box comes with Highway Products’ lifetime warranty.

WHY AN HPI™ Drop Door Semi Box



Highway Products boxes are completely reinforced to prevent the torsional forces that causes welds to crack and boxes to fail. The structure is the secret to our Million Mile Boxes.

WHY AN HPI™ Drop Door Semi Box

Highway Products boxes are completely reinforced to prevent the torsional forces that causes welds to crack and boxes to fail. The structure is the secret to our Million Mile Boxes.

You will never see bungies holding together an HPI Drop Door Box.  Thanks to ¼” stainless steel hinges with 3/8” knuckle secured by torx screws. Stainless steel T-Handles with 3/8 locking rods.

We use 1/8” 5052 marine grade aluminum to ensure you won’t deal with rust or deterioration of your toolbox over the years on the road in all different conditions.

Upgrade from Smooth Aluminum to Polished Stainless Steel Doors, or even Powdercoat your boxes for a unique look

Perfect to mount under bodies, or use for a variety of applications.

Everything build at Highway Products gets our Lifetime Guarantee

Checkout some photos and videos of Drop Door Semi Box.