The UWS 30" steel underbody tool box is the heavy-duty answer for a flatbed, dump truck or trailer body: a 14-gauge steel tub that takes the kind of loading and abuse that would dent an aluminum box, mounted either above or below the deck. It measures 30" long, 19" deep and 18" tall for 5.7ft³ of storage. The door opens a full 90 degrees and is held by stainless steel aircraft cables, a lockable T-handle give one-hand access, and a 1" drip rail runs right around the door opening so water sheds clear instead of running into the box. The MicroSeal gasket does the rest. The matte black powder coat resists corrosion and scratches. Two keys are in the carton; mounting hardware is not included.
What's Included:
UWS 30" steel underbody tool box
2 keys
Features
Extra-Thick 14-Gauge Steel Tub This is the reason to choose steel over aluminum. A 14-gauge tub holds heavy tools, chain, fittings and cargo that would mark a lighter box, and it puts up with being loaded carelessly for years.
5.7ft³ Mounted Above or Below the Deck At 30" x 19" x 18" it can be hung under a flatbed, dump truck or trailer body, or stood on top of the deck where headroom underneath is tight. Both are intended applications.
Door Opens a Full 90 Degrees The door drops all the way flat rather than stopping halfway, so the whole opening is available when you are loading long or awkward items. Stainless steel aircraft cables carry the door and hold it there.
1" Drip Rail Around the Door Opening A drip rail completely encircles the door opening so water running down the body sheds clear of the seal instead of tracking along it. Combined with the MicroSeal gasket, it is what keeps a box mounted in permanent road spray dry inside.
A lockable t-handle Keyed for security, foldable so nothing stands proud of the body, and operable with one hand. Two keys are included.
Matte Black Powder Coat A powder coat finish rather than paint, chosen to resist corrosion and scratching. On a steel box the finish is the corrosion protection, so keep it intact and touch up deep chips.
Fitment & Compatibility
Application
Fit
Flatbeds and stake beds
✓ Yes, above or below the deck
Dump trucks
✓ Yes, mounted clear of the hoist and tailgate swing
Trailer bodies
✓ Yes, where the frame carries the load
Work trucks that punish an aluminum box
✓ Yes, this is the reason the steel line exists
Standard pickup with a factory bed
✗ No, there is no usable frame space under a pickup bed
Fit guidance: Universal fit to any body with the room and the frame for it, above or below the deck. You need 30" of clear run, 19" of depth and 18" of height, plus enough ground clearance if you hang it underneath. This box ships freight only and is not a parcel item. Mounting hardware is not included; the matching UWS TBUB-1818-LB L-brackets are sold separately. Steel is the deliberate choice here: it is the tougher tub and the heavier one, so if payload matters more than impact resistance, the aluminum UWS underbody line is the better fit.
Specifications
Model: 30" Steel Single-Door Underbody Tool Box
UWS Part Number: ST-TBUB-30-MB
Type: Steel underbody box, mounts above or below a flatbed, dump or trailer body
Type: Bolted or welded above or below a flatbed, dump body or trailer body · Time: About 1 to 2 hours, longer if brackets have to be fabricated · Tools: Drill and bit set, ratchet and socket set, tape measure, level; a welder if you are welding brackets · Difficulty: Moderate. A truck up-fitter or equipment dealer is the right call if you are unsure of the frame
The box ships on its own with two keys. Mounting brackets and hardware are not included: UWS sells matching 18" x 18" L-brackets separately as part TBUB-1818-LB, which fit a box of this 18" depth and 18" height and include four 3" bolts, washers and locknuts. The underside of a steel box this heavy must be supported. Check for brake lines, fuel lines, wiring and the fuel tank before drilling. UWS is explicit that a tool box is not a place for flammables or hazardous material, so no fuel cans, solvents, propane or cutting torches. Never load past the vehicle manufacturer's rated capacity.
Resources
Everything you need for your UWS 30" Steel Underbody Tool Box, Matte Black Single-Door, in one place.
Warranty. Workmanship & Materials: Limited lifetime. Components & Parts: 1 year. Finishing & Coatings: 1 year. from UWS, covering workmanship and materials. Normal wear, damage from overloading, and damage from improper installation are not covered. UWS stocks handles, locks, gas struts, gaskets, cables and keys as individual service parts.
Free shipping. This item ships free to the lower 48 states. Because it is an oversized item, it ships by freight and typically arrives in 3 to 7 business days.
Inspect on delivery. Please inspect the packaging before signing. If you see any damage, note it on the delivery receipt and contact us right away, and we will make it right.
About UWS
UWS is short for United Welding Services, a truck storage brand in the CURT Group, a Lippert company. Most of the UWS catalog is aluminum and welded in Florida. This steel underbody line is the exception and UWS says so plainly: it is designed in the USA and imported from Mexico, because a 14-gauge steel service-body box is a different product built for a different job. The trade-off is deliberate. Steel costs you weight and it wants the finish kept intact, and in exchange you get a tub that shrugs off the kind of loading and abuse that lives under a dump body or a flatbed.
Everything about this box is sized for a work body rather than a pickup. The 14-gauge steel tub carries heavy, awkward, sharp-edged cargo without complaint. The door opens the full 90 degrees so you are not fishing past a half-open lid, and the 1" drip rail encircling the opening is the detail that separates a service-body box from a consumer one: it stops the water running off the deck above from finding its way over the door seal. UWS ships the box on its own and expects the up-fitter to supply the mount, which is why the matching UWS L-brackets are a separate part.
Prestige Truck is an authorized UWS dealer. Every box we ship is new and in the factory carton, covered by the full UWS factory warranty, and backed by the UWS replacement-parts program if a handle, strut, gasket or key ever needs renewing.
Frequently Asked Questions
Straight answers on specs, fit and support
Why steel instead of the aluminum UWS underbody box?
Impact resistance. A 14-gauge steel tub takes heavy, sharp, carelessly loaded cargo better than aluminum does. You pay for it in weight and in having to keep the finish intact, since on steel the powder coat is the corrosion protection. If payload and rust-free chips matter more, choose the aluminum line.
Can it mount on top of the deck instead of underneath?
Yes, both are intended. UWS designs this box to mount above or below a flatbed, dump truck or trailer body, so if ground clearance is tight you can stand it on the deck instead of hanging it.
Is any mounting hardware included?
No, the box and two keys only. UWS sells matching 18" x 18" L-brackets separately as TBUB-1818-LB, and those do include four 3" bolts, washers and locknuts. They suit this box's 18" depth and 18" height.
What is the drip rail for?
It is a 1" rail that runs the whole way around the door opening, so water running down the body sheds clear of the door seal rather than tracking along it and finding a way in. On a box that lives in permanent road spray it does more for dryness than the gasket alone.
Where is it made?
UWS says it plainly and so do we: this steel line is designed in the USA and imported from Mexico. The aluminum UWS boxes are the ones fabricated and welded in Florida.
What does the warranty cover?
Limited lifetime on workmanship and materials, one year on components and parts, and one year on the finish and coatings. Damage from overloading or from an inadequate mount is not covered.
Mark K.
Look is great. 100 lbs
Look is great. 100 lbs lighter than my 2nd pick. Lid lock and opening are smooth. Only minor knock I give is the the tie down hooks are hard to install - thinking I should have done them before installing.
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The toolbox is nice. I
The toolbox is nice. I think Ill get a lot of years of service out of it. I like how the lid opens and the tie downs are a nice touch. It seems to be well built. And tough. Im pleased with my purchase and would buy another one.
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