This is the UWS Secure Lock under tonneau chest box, built to live in the bed underneath a tonneau cover. It stands just 16.5" tall with an offset lid, holds 8.85ft³, and locks with dual Secure Lock twist handles that sit nearly flush in the front panel. The tub is a single piece of 0.058" aluminum, the lid is UWS's patented RigidCore foam-filled design so it will not flex or bind, and a MicroSeal gasket runs the full perimeter of the opening to keep rain and dust out. The finish is bright aluminum diamond plate. This is the heavy-packaging version of the box: mechanically identical to the standard part, but crated for parcel carriage so it can ship without freight. It is assembled in the USA and backed by a limited lifetime warranty.
What's Included:
UWS 48" Under Tonneau Chest Box in Bright Aluminum, part EC20501
2 keys
Mounting hardware kit, on the models that include one (see the note below)
MAY NOT BE INCLUDED: UWS states that not all chest box models ship with the mounting hardware kit, and does not say which. Budget for UWS kit #003-CBOXMK, or two 5/16" or M8 bolts with four washers and two lock nuts, in case yours arrives without it
UWS installation sheet, product literature and warranty information
Features
Dual-Locking Secure Lock Handles Secure Lock twist handles lock on both sides of the box and are joined by a connecting rod, so it opens from either side and locks from either side. They sit almost flush in the front panel, which is what lets the box live under a tonneau cover without fouling it.
Fits Under Most Tonneau Covers The box stands just under 16.5" tall and the lid is offset toward the rear, so it clears the underside of most tonneau covers and can still be opened with the cover fitted. Measure your own cover before ordering, because the lid travel can be limited by the cover style.
Self-Opening Lid Release the Secure Lock handles and the lid lifts and stays up on its own, close to a full 90 degrees. That is a genuinely useful detail when both hands are full or you are working in the dark: you are not holding a heavy lid open with a shoulder while you dig for a socket.
Extra-Thick 0.058" One-Piece Aluminum Tub The tub is formed from a single piece of 0.058" aluminum rather than welded up from thinner panels, so there are fewer seams to leak or split and the box keeps its shape when it is loaded with heavy hand tools, cordless kits and chain. Aluminum also means it will not rust out from the inside the way a painted steel box does once the coating is chipped, which matters on a box that lives outdoors and gets road salt thrown at it every winter.
MicroSeal Weather Gasket A MicroSeal gasket runs the full perimeter of the opening and compresses as the lid closes, sealing out rain, road spray, dust and the fine grit that ruins bearings and fastener threads. It is the part of a tool box most owners only think about after they have found standing water inside a cheaper one.
Patented RigidCore Foam-Filled Lid UWS fills the lid with a solid foam core instead of leaving it hollow. That is what stops a long lid from flexing in the middle, binding in its own opening or drumming as you drive. On a 48" lid this is the difference between a box that still latches cleanly after a few years and one that has to be pushed down to catch.
Connecting Rod for Either-Side Operation The two handles are tied together by an internal rod, so the box opens from the driver side or the passenger side without walking around the truck. On a wide bed that is the difference between grabbing a tool and climbing up into the bed to get it.
Limited Lifetime Warranty UWS backs the box with a limited lifetime warranty, with one year on the finish and one year on parts. That is the manufacturer telling you what it expects the welded aluminum structure to do over the life of the truck.
Fitment & Compatibility
Application
Fit
Full-size pickup with a tonneau cover
✓ Yes, this is the intended application
Full-size pickup with no cover
✓ Yes, the low profile still gives a clear rear view
Mid-size pickup
● Measure first, the box is 48" wide across the bed
Fit guidance: The box stands 16.5" tall with an offset lid so it clears the underside of most tonneau covers. Cover styles differ, so measure the clearance under your own cover at the point the box will sit, and note that lid travel toward the full 90 degrees can be limited by the cover. Mounting hardware kit #003-CBOXMK is sold separately.
Specifications
UWS Part Number: EC20501
Box Style: Under Tonneau Chest Box, Low Profile
Finish: Bright Aluminum diamond plate
Material: 0.058" one-piece aluminum
Storage Capacity: 8.85ft³
Overall Length: 48"
Overall Width: 24.5"
Overall Height: 16.5"
Interior Tub Length: 47"
Interior Tub Width: 24"
Interior Tub Depth: 3.75"
Lower Tub Width: 9.75"
Lid Type: Single Lid
Latch / Handle: Secure Lock Handle
Lid Core: Patented RigidCore foam-filled
Weather Sealing: MicroSeal full-perimeter gasket
Carrying Handles: Without Carrying Handles
Installation Difficulty: Easy
Product Weight: 44 lb
Shipping Weight: 52 lb
UPC: 672078083249
Warranty: Limited lifetime, one-year finish, one-year parts
Origin: Assembled in the USA
Installation
Type: Bolt-in · Time: About 30 to 60 minutes · Tools: Socket set, drill and bit if your application is not pre-drilled, tape measure, marker; a second person to lift and hold the box · Difficulty: Easy, DIY-friendly
Set the box in the bed against the bulkhead, check the lid clears the underside of your tonneau cover through its full travel before you drill, then mark through the mounting slots and bolt down. Check underneath for fuel and brake lines before drilling.
Resources
Everything you need for your UWS 48" Secure Lock Under Tonneau Chest Box, Bright Aluminum, in one place.
Warranty. UWS limited lifetime warranty on the box, with one year on the finish and one year on parts. Damage from overloading, accident, modification or improper installation is not covered, and the warranty is offered to the original purchaser.
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, United Welding Services, has been welding aluminum truck boxes in Florida since 1988. It is now part of the Lippert and CURT Group family, which is what gives a box at this price a real dealer network, real parts support and a warranty that means something years later. What has not changed is where the boxes are made: UWS designs, fabricates and welds them at its own plant rather than importing finished bodies, and that is visible in the details that cannot be fixed after the fact, such as square lids, consistent welds and gaskets that meet cleanly all the way around the opening.
Two UWS features do most of the work in this under tonneau chest box. The first is the patented RigidCore lid, filled with a solid foam core instead of left hollow, which is what stops a long lid flexing in the middle, drumming at speed or binding in its own opening as the box ages. The second is MicroSeal, a full-perimeter gasket that compresses as the lid closes and keeps out the rain, road spray and fine grit that ruin the contents of a cheaper box. Underneath both is a 0.058" one-piece aluminum tub, thicker than most of the competition and immune to the rust that eventually kills a painted steel box.
Prestige Truck is an authorized UWS dealer. Every box we ship is new, factory-packed, covered by the full UWS limited lifetime warranty and supported by UWS's US-based parts and service team.
Compare The Range
How this compares to similar models
The closest alternatives side by side, so you do not have to keep tabs open.
Model
This OneUWS 48" Secure Lock Under Tonneau Chest Box, Bright Aluminum (EC20501)
RigidCore Strength Test: Tool Box Vs. Pickup Truck
UWS drives a pickup onto one of its RigidCore lids.
It is a marketing stunt and it is also the clearest demonstration of what the foam core actually does, which is stop a long lid flexing, denting or binding in its own opening. This box uses the same RigidCore lid.
MicroSeal Weather Test: Mud And A Pressure Washer
UWS buries a box in mud and then turns a pressure washer on it to show what the MicroSeal gasket keeps out.
Worth two minutes if you are deciding between this and a cheaper box with a plain foam strip, because sealing is the thing you only notice once it has failed.
How To Measure Your Truck Bed Before You Order
UWS walks through measuring a truck bed properly, which is the step that prevents almost every returned tool box.
Do this before you order: the measurement that matters for a box like this is the flat space or rail-to-rail width you actually have, not the advertised bed length.
Frequently Asked Questions
Straight answers on specs, fit and support
What are the actual dimensions, and will it fit my truck?
The box is 48" long, 24.5" deep and 16.5" tall overall, and it holds 8.85ft³. The usable tub inside measures 47" x 24" x 3.75". Measure the flat space you have available before ordering.
Is the mounting hardware included?
Possibly, and we would rather tell you plainly than guess. UWS lists a mounting hardware kit in the parts list for this box, then adds that "not all models include mounting hardware kit" without saying which. So budget for UWS kit #003-CBOXMK, or for two 5/16" or M8 bolts with four washers and two lock nuts, in case yours arrives without it. We have asked UWS to confirm.
What is the difference between this and the standard UWS part?
This is the heavy-packaging version of the UWS box, crated for parcel shipment rather than freight. The box, the materials and the warranty are the same.
How well does it keep water out?
A MicroSeal gasket runs the full perimeter of the opening and compresses as the lid closes. No tool box is a submarine, and a box that is pressure washed straight at the seam or parked nose-down in standing water can still take some in, but in normal service it stays dry inside. Keep the gasket clean and it will keep sealing.
What is the finish, and how does it hold up?
Bright aluminum diamond plate, which is the mill finish of the aluminum itself rather than a coating. It cannot chip or peel because there is nothing on top to come off, and aluminum does not rust. It will dull and pick up a patina over the years, which most owners either like or polish back.
Does the lid stay open on its own?
Yes. Release the Secure Lock handles and the RigidCore lid lifts and holds itself open at close to 90 degrees, so you have both hands free. The foam-filled lid is light enough for the mechanism to manage but stiff enough not to flex on the way up.
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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I never knew how much I needed this
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Jeffrey P.
Better then expected.
Searched for about 6 months to find the tonneau cover. I really wanted the security of a hard top without sticking above the bed rails it checked those boxes. I also did not want to drill my truck bed. The install was super simple my wife and I had it on the truck in about a half an hour.
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Joseph A.
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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UWS 48" Secure Lock Under Tonneau Chest Box, Bright Aluminum (EC20501)
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