The UWS 48" Secure Lock Under Tonneau Chest Box solves the problem every owner of a covered bed runs into: a normal chest box is too tall to live under a tonneau cover. This one is 16.5" tall and low-profile, with the lid offset toward the rear so it can still swing open in the space a cover leaves, and it holds 8.85ft³ despite that, because UWS recovered the volume through the offset rather than through height. It measures 48" long, 24.5" wide and 16.5" tall overall. Instead of paddle handles it uses two Secure Lock twist T-handles, both lockable, connected by an interior rod in a protective enclosure so you can unlock from one side, open from either, and make prying difficult. The tub is 0.058" aluminum welded into a single piece in the USA, the lid is UWS's patented RigidCore foam-filled construction, and a MicroSeal gasket seals the full lid seam against water, dirt and insects. The lid self-opens to a full 90 degrees, though UWS is straightforward that your cover style may limit how far it actually travels. Empty weight is 40 lb.
What's Included:
One UWS 48" Secure Lock Under Tonneau Chest Box, Matte Black Aluminum
Two keys (UWS install sheet Parts List: 1 chest box, 2 keys, 1 mounting hardware kit)
MicroSeal gasket, factory-fitted around the lid seam
Self-opening gas struts, factory-fitted
Mounting hardware kit, but see the note below: UWS states that not all models include one
UWS installation manual
UWS limited lifetime warranty
UWS prints this caveat on its own Parts List page: "Not all models include mounting hardware kit. You may need to purchase your own hardware to install this chest box." UWS does not say which models, so treat the kit as not guaranteed.
Features
8.85ft³ of Locked, Sealed Storage The SLC-48-MB measures 48" long by 24.5" wide by 16.5" tall overall, with a 47" by 24" tub inside, and UWS rates it at 8.85ft³. That is a genuinely large number for a box that still slides under a tonneau cover, and it comes from the offset lid rather than from extra height.
Sized to Live Under a Tonneau Cover At 16.5" tall this box is built to clear most tonneau covers, and the lid is offset toward the rear so it can open without fouling the cover. UWS is careful to say the lid self-opens to a full 90 degrees but that the cover style may limit how far it actually gets, and that is the honest way to put it: measure your cover's inside height before you order.
Patented RigidCore Foam-Filled Lid The lid is not a hollow shell. UWS fills it with a hardening, expanding foam pressed between two aluminum plates, and the foam sets into a solid structure that carries load across the whole panel. In practice that means the lid does not bow when someone stands on it, and it does not warp out of shape over a few summers and start binding on the gasket. RigidCore is patented and it is the single biggest difference between this box and a cheap aluminum one.
MicroSeal Gasket Around the Full Lid Seam A MicroSeal gasket runs the entire seam where the lid meets the tub, which is what keeps rain, road spray, dust, grit and insects out of the box. It is the difference between finding your tools dry and finding them under a film of red dust after a week on a job site.
Secure Lock T-Handles, Lockable From Either Side Instead of paddle handles this box uses two Secure Lock twist T-handles. Both are lockable, so you can lock the driver side, the passenger side, or both, and an interior rod lets you open it from whichever side you are standing on once it is unlocked. The rod sits in a protective enclosure that resists prying.
Self-Opening Lid, One-Handed Gas struts take the weight of the lid and hold it open, so you can flip the latch and the lid rises on its own. It sounds like a small thing until you are carrying a cordless drill in one hand and a coffee in the other.
Welded One-Piece Aluminum Tub The tub is 0.058" aluminum diamond plate welded into a single piece rather than riveted or folded, so there are no seams to work loose and no fasteners to shear. Aluminum also keeps the box light, at 40 lb, and it does not rust when the finish gets scratched.
✓ Yes, forward of the wheel wells against the bulkhead. Measure your own bed; mid-size beds run roughly 44" between the wells and about 56" at the bulkhead.
✓ Yes, fits between the wheel wells as well as forward of them. Full-size beds run roughly 49" to 51" between the wells and about 62" to 66" at the bulkhead.
3/4-ton and 1-ton pickups (F-250/350, Silverado 2500/3500, Ram 2500/3500)
✓ Yes, fits between the wheel wells as well as forward of them. The widest beds in the range, so a long chest has the best chance here.
Flatbeds, service bodies, trailers, shop and garage use
✓ Yes. This is a free-standing chest, so it needs a flat floor and nothing else.
Under a tonneau cover
● Designed for it. The box is 16.5" tall, so measure the inside height of your cover at the bulkhead before ordering.
Fit guidance: This is a universal-fit chest box, not a vehicle-specific kit, so there is no year, make and model list to check. What matters is one measurement: the 48" overall length of the box against the usable width of your bed. A chest sits across the bed with its length running from rail to rail, normally pushed forward against the bulkhead where the bed is at its widest. Beds are narrower between the wheel wells than they are at the bulkhead, so measure both. Also check that the 16.5" height still lets your rear window and any bed cover work, and remember that a bed liner takes an inch or so off every internal measurement. The box is free-standing; UWS supplies no bed-specific mounting kit.
Specifications
UWS Part Number: SLC-48-MB
Product Type: Aluminum chest tool box
Material: Aluminum diamond plate, welded single-piece tub
Finish: Matte black powder coat
Overall Length: 48"
Overall Width: 24.5"
Overall Height: 16.5"
Tub Length: 47"
Tub Width: 24"
Tub Height: 3.75"
Lower Tub Width: 9.75"
Storage Capacity: 8.85ft³
Tub Style: Standard
Profile: Low Profile
Lid Type: Single Lid
Latch Type: Secure Lock twist T-handles (2), lockable from either side
Carrying Handles: No
Product Weight: 40 lb
Shipping Weight: 46 lb
Shipping Method: Freight (LTL) only
Installation Difficulty: Easy
UPC: 672078082983
Warranty: Limited lifetime, with one year on the finish and one year on the parts
Country of Origin: USA
Installation
Type: Free-standing in the truck bed, on a flatbed or in the shop; no vehicle-specific mounting kit required · Time: About 10 minutes · Tools: A tape measure, and a second person for the lift at 40 lb · Difficulty: Easy, no drilling required
A chest box does not bolt to the bed rails; it sits on the bed floor, normally pushed forward against the bulkhead where the bed is widest. Measure your bed before ordering: this box is 48" long, and beds are narrower between the wheel wells than at the bulkhead. Once it is in, secure it. An unsecured chest will slide forward under heavy braking, so run straps to the bed's tie-down points or bolt it down. If you are running a bed liner, remember it takes an inch or so off every internal measurement. One thing to know before you plan the install: the Parts List in UWS own chest box manual lists a mounting hardware kit, then footnotes that not all models include one and that you may need to buy your own hardware. UWS does not publish which models do. Budget for supplying your own bolts and treat the kit as a bonus rather than a certainty. For an under-tonneau install, check the inside height of your cover at the bulkhead against the box's 16.5" and confirm the lid can still swing before you commit.
Resources
Everything you need for your UWS 48" Secure Lock Under Tonneau Chest Box, Matte Black Aluminum, 8.85ft³, in one place.
Warranty. UWS limited lifetime warranty on the box, with one year on the finish and one year on the parts. The warranty covers defects in materials and workmanship; it does not cover damage from overloading, misuse, accident or improper installation, and it does not cover normal wear on the finish.
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, and the name is the point: every UWS box starts as flat aluminum sheet and is welded into a single-piece tub rather than riveted or folded together. The company builds at its own plant in Perry, Florida, and it has been supplying the truck accessory trade long enough that the diamond plate box with the blue UWS badge is a familiar sight on job sites. UWS is part of the CURT Group, which in turn belongs to Lippert, so behind a fairly specialized Florida welding shop sits a full national parts and warranty network.
Two pieces of engineering separate a UWS box from a generic aluminum one. The first is the patented RigidCore lid: instead of a hollow shell, the lid is a pair of aluminum plates completely filled with a hardening, expanding foam, which sets into a solid structure and stops the lid bending, warping or binding after a few years of being leaned on. The second is the MicroSeal gasket, which lines the entire seam where the lid meets the tub and keeps water, dust, grit and insects out of the box rather than merely slowing them down. Both are backed by a limited lifetime warranty on the box, with one year on the finish and one year on the parts.
Prestige Truck is an authorized UWS dealer. Every box we ship is new, in the original UWS carton, built in the USA, and covered by the full UWS factory warranty.
Frequently Asked Questions
Straight answers on specs, fit and support
Will the SLC-48-MB fit my truck bed?
Measure before you order. The box is 48" long and it sits across the bed, so what matters is your bed's usable width. Full-size beds are roughly 49" to 51" between the wheel wells and about 62" to 66" at the bulkhead; mid-size beds are roughly 44" and 56". At 48" this one fits between the wheel wells on a full-size bed and forward of them on a mid-size. A bed liner takes another inch or so off.
How much does it actually hold?
UWS rates it at 8.85ft³, and the tub measures 47" by 24" with a 3.75" depth at the step. That figure comes from UWS's own dimension drawing for this part number, and we have checked it against the spec table on the same page.
Does it lock, and how many handles does it have?
Yes. It has a single key-operated stainless steel paddle handle, recessed into the box so it cannot easily be levered. Keys are supplied.
What is RigidCore, and does it matter?
RigidCore is UWS's patented lid construction: two aluminum plates with a hardening, expanding foam filling the space between them. It matters because an unsupported aluminum lid this size will bow when it is leaned on and eventually warp enough to bind on the gasket. A RigidCore lid stays flat, which is also what keeps the MicroSeal gasket sealing years later.
Is it weatherproof?
It is well sealed rather than submersible. A MicroSeal gasket runs the entire seam where the lid meets the tub and keeps out rain, road spray, dust and insects, which is what a bed box actually faces. It is not rated as a waterproof case, so treat pressure washing straight at the seam and standing water inside the bed as things to avoid.
Does it come with mounting hardware, and how does it ship?
Maybe, and we would rather tell you that than guess. The Parts List in UWS's own chest box manual reads: one chest box, two keys, one mounting hardware kit, and then footnotes that not all models include the kit and that you may need to purchase your own hardware. UWS does not publish which models are which, so plan on supplying your own bolts. It ships by freight (LTL) at a shipping weight of 46 lb, so expect a delivery appointment and a truck rather than a courier. The box itself weighs 40 lb, which is a two-person lift into the bed.
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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Mark
A must have
I really like this mat. I was apprehensive at first but, the mat does a great job of keeping things from sliding around without having to secure it. perfect fit. But i think i will be adding some short screws to secure the mat to the DECKED system.
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Roy L.
I never knew how much I needed this
As with all BAK covers, the quality is amazing. What I didnt fully appreciate until installing was the ease of opening - especially in a lifted truck. No more need to find the right handhold. Just roll it back with a single hand. Its also great to see out of my rear window when fully open - something you lose with the fold back covers. Customer service is awesome. I has an installation question and the representative stayed on the line as I adjusted an alignment to ensure I did it properly.
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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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