Best Underbody Tool Box For Flatbed: 10 Options Compared

#1 · Best Overall

1. Buyers Products 1762645

• Dimensions: 60"L x 24"W x 24"H
• Material: Aluminum
• Weight: 101.5 lb

Best for: Wide-access trailer storage.

Why it ranks #1: Made for flatbeds, platforms, and step-deck trailers, this 60-inch, 0.125-inch aluminum box has double doors and no center post.

Unobstructed double barn doors provide clear access to this 60-inch Buyers Products box’s interior, without a center post interrupting the opening. Its .125-inch smooth aluminum body offers corrosion-resistant storage for flatbeds, platforms, step-deck trailers, dump bodies, and compatible medium- to heavy-duty trucks.

The 24-by-24-by-60-inch interior gives this box a notably broad storage bay for chains, straps, tools, and service equipment, while the center-post-free doors make loading and retrieving bulky items more direct. The .125-inch aluminum body is specified as corrosion resistant, a useful material choice for trailer-mounted storage. Cam-lock hardware is included, and the product information describes padlock-ready cam security. At 101.5 pounds, the listed weight makes planning installation and support important for the intended mounting position.

Skip it if you need a lighter, narrower 48-inch aluminum box; VEVOR’s UTTB-481718 is listed at 37.8 pounds.

This is a fit for flatbed or step-deck operators storing bulky equipment who value a clear, wide opening. Its 24-inch depth and 101.5-pound weight make space and installation capacity key considerations.

Listed on Amazon as: Buyers Products 1762645 60- Inch Aluminum Underbody Truck Tool Box

#2 · Longest Single Door

2. UWS EC40111

• Dimensions: 60"L x 19"W x 18"H
• Material: Aluminum
• Weight: 55 lb

Best for: Bed-clear flatbed storage.

Why it ranks #2: Purpose-built for flatbeds and trailers, this 60-inch single-door aluminum box has a welded 0.075-inch tub and 11-cubic-foot capacity.

A welded, one-piece 0.075-inch aluminum tub gives the UWS EC40111 a 60-inch underbody storage bay while leaving the flatbed available for cargo. Its 19-by-18-inch dimensions and 11-cubic-foot capacity suit owners seeking a long, open storage area beneath a truck or trailer bed.

Mounting underneath the side of a flatbed, dump truck, or trailer keeps tools off the main deck, so cargo can still use the bed surface. The one-piece welded aluminum tub is specified as corrosion resistant, supporting use in exposed vehicle settings. Its 60-inch length and 11-cubic-foot capacity provide a substantial open bay for organized tool storage. UWS also identifies a MicroSeal gasket for sealing out dust, debris, and moisture; the supplied listing describes a single-door configuration.

Skip it if you need double barn doors and a center-post-free opening; Buyers Products 1762645 provides that access arrangement.

The EC40111 suits flatbed owners who want a long underbody bay and need the deck free for other cargo. Consider its single-door layout and 19-inch width when planning tool access and mounting.

Listed on Amazon as: UWS EC40111 60-Inch Heavy-Wall Aluminum Single-Door Flatbed Underbody Tool Box

#3 · Best Barn Doors

3. Buyers Products 1705203

• Dimensions: 30"L x 18"W x 18"H
• Material: Aluminum
• Weight: 36 lb

Best for: Weather-sealed barn-door box.

Why it ranks #3: Its 30 x 18 x 18-inch diamond-tread aluminum body is explicitly for flatbeds and adds a rain gutter, bulb seal, and compression latch.

A built-in rain gutter, bulb seal, and locking compression latch give this 30-inch Buyers Products box a weather-conscious closure for flatbeds, trailers, and work trucks. Its .100-inch diamond-tread aluminum body combines corrosion resistance with barn-door access for tools stored beneath the vehicle bed.

The 30-by-18-by-18-inch box offers a shorter footprint than the 48- and 60-inch options, which can suit vehicles with limited underbody length. Its rain gutter and bulb seal are specified to help keep tools dry and dust-free, while the die-cast compression latch locks the doors and creates a tight seal. A continuous aluminum hinge with a solid 1/4-inch pin and three-point locking adds stated security details. The listed 36-pound weight can also inform installation planning.

Skip it if you need a longer 48-inch bay; STMGW’s UTTB0704 measures 48 × 18 × 18 inches and uses cam-lock hardware.

Choose this for a shorter underbody space where sealed barn-door storage and a compression latch matter. Its 30-inch length limits long-item capacity, so match the box dimensions to the tools and mounting area.

Listed on Amazon as: Buyers Products 1705203 Underbody Truck Tool Box with Barn Doors, 18x18x30 Inch, Diamond Tread Aluminum, Made in USA, Compression Latch, Weather Resistant, Toolbox for Flatbeds, Trailers & Work Trucks

#4 · Compact Flatbed Fit

4. S.Walt 36-Inch Aluminum Box

• Dimensions: 36"L x 18"W x 18"H
• Material: Aluminum

Best for: Compact aluminum flatbed box.

Why it ranks #4: Designed for flatbeds and trailers, this 36 x 18 x 18-inch aluminum box keeps storage beneath the frame and has a lockable, weather-resistant design.

At 36 by 18 by 18 inches, this S.Walt aluminum box puts lockable storage beneath a flatbed or trailer while keeping the deck open for hauling. Its 0.100-inch diamond-plate construction combines the specified material thickness with a weather-resistant, underbody-focused format for work vehicles.

The 36-inch length suits buyers whose mounting space cannot accommodate a longer box, and the underbody placement leaves the flatbed surface available for materials or oversized loads. Its aluminum body is listed as 0.100-inch thick diamond plate, giving the storage shell a defined construction specification. Lockable and weather-resistant features support keeping tools secured and sheltered in a trailer or work-truck setup. The supplied information lists the main unit only, so it does not identify included keys or separate installation hardware.

Skip it if you want a listed 48-inch aluminum box with two keys included; VEVOR’s UTTB-481718 specifies both.

Choose this for a flatbed or trailer needing a 36-inch aluminum box that keeps storage below the hauling surface. The included-components listing is main unit only, so plan around that stated package.

Listed on Amazon as: 36 Inch Aluminum Underbody Truck Tool Box, Heavy-Duty Flatbed Tool box for Trucks & Trailers, Lockable Waterproof Storage Box– 0.100 in. Thick Aluminum Diamond Plate, Matte Black

#5

5. Buyers Products 1702305

• Dimensions: 36"L x 18"W x 18"H
• Material: Alloy Steel
• Weight: 76 lb

Best for: Steel work-truck storage.

Why it ranks #5: This flatbed-compatible 36 x 18 x 18-inch steel box uses 14-gauge construction and a stainless steel compression latch with keys included.

A 14-gauge steel body and stainless compression T-handle latch give this 36-by-18-by-18-inch Buyers Products box a rugged, secured option for flatbeds and trailers. The latch pulls the recessed drop door against its gasket, helping reduce rattling and protect stored tools during travel.

The 36-inch length and 18-inch height provide a defined underbody storage footprint for tools, parts, and supplies, while 14-gauge steel is specified for demanding work-truck applications. Its stainless compression latch draws the recessed drop door firmly against the gasket; that combination is intended to limit rattling and improve weather protection on the road. A continuous hinge supports the door arrangement, and the included keys suit locking up equipment. Check the listed dimensions against the intended mounting position.

Skip it if you want a longer 60-inch aluminum box with unobstructed double-door access; Buyers Products 1762645 offers that configuration.

This suits work-truck and flatbed owners who want steel storage, a compression latch, and a 36-inch footprint. Account for its 76-pound listed weight and verify the underbody space before choosing it.

Listed on Amazon as: Buyers Products 1702305 36 x 18 x 18 Inch Steel Underbody Tool Box

#6

6. VEVOR 48-Inch Aluminum Box

• Dimensions: 48"L x 17"W x 18"H
• Material: Aluminum
• Weight: 37.8 lb

Best for: Long aluminum tool storage.

Why it ranks #6: The 48 x 17 x 18-inch aluminum box is suited to trucks and trailers, with a rubber sealing strip, T-handle latch, and two keys.

The 48-by-17-by-18-inch aluminum body offers long underbody storage while weighing 37.8 pounds, making this VEVOR box a practical format for tools or camping equipment. Its rubber sealing strip and lock with keys add weather-minded closure and basic access control for truck, van, or trailer use.

With a 48-inch length and aluminum construction, this box provides a long storage bay without the listed weight of the steel options. The rubber sealing strip forms a tight seal when closed, supporting protection from water and dust as described in the product information. A lock and two keys secure the contents, while the stated uses include trucks, vans, and trailers; the box may also be installed at a camper’s back or on a pickup rack. Installation guidance is shown in the setup video.

Skip it if you need a 60-inch bay with double barn doors; Buyers Products 1762645 provides that longer, unobstructed-access format.

Pick this VEVOR for long tools or camping gear when an aluminum box and 48-inch length fit the vehicle. Its 17-inch width and intended mounting location still need to suit the available space.

Listed on Amazon as: VEVOR Underbody Truck Box, 48"×17"×18" Pickup Storage Box, Heavy Duty Aluminum Diamond Plate Tool Box with Lock and Keys, Waterproof Trailer Storage Box with T-Handle Latch for Truck, Van, Trailer

#7

7. STMGW 48-Inch Aluminum Box

• Dimensions: 48"L x 18"W x 18"H
• Material: Aluminum
• Weight: 50 lb

Best for: Padlock-ready aluminum storage.

Why it ranks #7: This 48 x 18 x 18-inch aluminum box is described for flatbed use and has double barn doors plus cam-lock hardware for a separate padlock.

The 48-by-18-by-18-inch STMGW box pairs a smooth aluminum body with cam-lock hardware that accepts a personal padlock, giving flatbed owners a long, lockable underbody storage bay. Its listed weather-resistant and moistureproof features address protection for tools stored on a truck or trailer.

A 48-inch length provides room for larger tools and equipment, while the aluminum construction is described as durable and corrosion resistant. The cam-lock hardware accepts a personal padlock, purchased separately, so buyers can use their own locking setup. Product information also lists the box as weathertight and moistureproof, supporting storage in exposed vehicle locations. A double barn-door design is described in the additional listing description for side access; the stated 50-pound weight is useful when planning installation.

Skip it if you want a box with keys included rather than a separate padlock; Buyers Products 1705203 lists keys in the package.

This suits flatbed users wanting a long aluminum bay and control over their padlock choice. Allow for the separately purchased padlock and check that the 48-inch body fits the intended underbody position.

Listed on Amazon as: Aluminum Underbody Truck Tool Box With Cam Lock (48"×18"×18")

#8

8. VEVOR 36-Inch Aluminum Box

• Dimensions: 36"L x 14"W x 16"H
• Material: Aluminum
• Weight: 24.7 lb

Best for: Smaller-space aluminum storage.

Why it ranks #8: A smaller 36 x 14 x 16-inch aluminum option for trucks and trailers, it includes a T-handle latch and two keys.

A 36-by-14-by-16-inch footprint makes this VEVOR aluminum box a compact underbody choice for trucks, vans, and trailers with limited mounting room. The rubber sealing strip, lock, and included keys add closure and security features, while its listed 110-pound maximum load provides a stated capacity boundary.

The compact dimensions can suit tighter underbody locations than a 48-inch box, and the aluminum body is specified as rust- and corrosion-resistant. A rubber strip creates a tight seal when closed, supporting protection from water and dust as described; the lock and two keys help secure stored maintenance or camping gear. The listing gives a maximum weight recommendation of 110 pounds, which helps set a practical loading limit. It also identifies pickup racks and camper locations as possible placements.

Skip it if you need more width for bulky gear; VEVOR’s UTTB-481718 measures 17 inches wide and 48 inches long.

This fits buyers with a restricted mounting area who need lockable aluminum storage for everyday tools. Its 14-inch width and 110-pound maximum recommendation define the space and load limits to consider.

Listed on Amazon as: VEVOR Underbody Truck Box, 36"×14"×16" Pickup Storage Box, Heavy Duty Aluminum Diamond Plate Tool Box with Lock and Keys, Waterproof Trailer Storage Box with T-Handle Latch for Truck, Van, Trailer

#9

9. COOLBAG 48-Inch Steel Box

• Dimensions: 48"L x 18"W x 18"H
• Material: Alloy Steel

Best for: Two-box flatbed storage.

Why it ranks #9: This two-box package offers lockable, weathertight steel storage and lists flatbeds among its uses; each box measures 48 x 18 x 18 inches.

The two-box package pairs a 48-by-18-by-18-inch footprint with lockable, weathertight steel storage, giving flatbed owners two separate places to organize tools below the bed. Its T-handle locks and keys add a security feature for equipment stored between jobs or during travel.

Each listed box measures 48 by 18 by 18 inches and uses alloy steel, so the set offers substantial-length storage in a material suited to work-truck use. The lockable, weathertight specification supports keeping stored items secured and sheltered. A two-box arrangement can separate equipment by task or vehicle location, while the under-mount format keeps the flatbed available for cargo. The supplied information does not specify mounting hardware or a seal design, so installation details should be checked before planning the setup.

Skip it if you need a single compact box; VEVOR’s 36 × 14 × 16-inch UTTB-361416 is a smaller one-box option.

Choose this set if a flatbed needs two lockable storage locations and the 48-inch boxes suit the available underbody space. It is less suitable when one compact container or aluminum construction is the priority.

Listed on Amazon as: 2 Pack Underbody Truck Tool Box, 48"x18"x18" Heavy Duty Steel Storage Chest with T-Handle Lock & Keys, Waterproof Under Mount Toolbox Organizer for Pickup, Trailer, RV, Flatbed, Powder Coated

#10

10. Vigorighter 24-Inch Steel Box

• Dimensions: 24"L x 12"W x 14"H
• Material: Alloy Steel

Best for: Two compact steel boxes.

Why it ranks #10: The two 24 x 12 x 14-inch steel boxes are listed for flatbeds and have lockable, powder-coated construction, but offer the smallest dimensions here.

Two 24-by-12-by-14-inch steel boxes give this Vigorighter set a split-storage approach for flatbeds, trailers, RVs, and pickups. The rigid powder-coat finish and lockable format support organized tool storage in compact spaces, while the two-box arrangement can keep equipment separated by vehicle location or task.

Each box uses alloy steel and measures 24 by 12 by 14 inches, making the set suited to smaller underbody storage spaces rather than one long bay. The rigid powder-coat finish is listed alongside corrosion-resistant construction, supporting use around work sites and vehicles. Verified product information also describes fully welded seams as helping keep rain, dust, and grime out. The lockable feature provides a way to secure contents; the stated maximum weight recommendation is 20 pounds, so loading should stay within that limit.

Skip it if you need a much higher stated load recommendation; VEVOR’s UTTB-361416 lists a 110-pound maximum.

This set suits buyers who prefer two small lockable steel storage locations for light tools or accessories. Its 20-pound maximum recommendation is a clear limit for heavier equipment or a larger flatbed loadout.

Listed on Amazon as: 24 Inch Underbody Tool Boxes for Truck 2 Pack, 24 x 12 x 14 Inch Steel Under Body Storage Box with T-Handle Latch, Waterproof Heavy Duty Toolbox for Pickup Truck RV, Black (Pack of 2)