Best Flatbed Trailer Tool Box for Underbody and Trailer Storage

#1 · Best Overall

1. VEVOR 48-Inch Aluminum Underbody Box

• Dimensions: 48"L x 17"W x 18"H
• Material: Aluminum
• Weight: 37.8 lb
• Capacity: 13 kg

Best for: Lightweight aluminum underbody storage.

Why it ranks #1: Its 48-by-17-by-18-inch aluminum underbody format suits full-size flatbed storage, and it includes a lock, two keys, and a rubber sealing strip.

At 37.8 pounds, this 48-inch VEVOR box combines a comparatively light listed weight with aluminum construction, making it an option for buyers who want long underbody storage without a steel enclosure. Its rubber sealing strip and lock with keys support protected, organized access on trucks, trailers, vans, or pickup racks.

The 48 × 17 × 18-inch dimensions provide a long compartment for maintenance tools or camping equipment, while the aluminum body keeps the listed weight to 37.8 pounds. A rubber sealing strip forms a tight seal when closed, helping protect contents from water and dust, and the T-handle latch with keys adds lockable access. VEVOR also identifies use on truck and trailer bottoms or pickup racks, so placement can suit more than one vehicle layout.

Skip it if you need a stated load rating above 13 kg; FORWODE lists a 75-pound maximum weight recommendation.

Consider this for truck, trailer, van, or pickup-rack owners who value a long aluminum compartment and a sealing strip. Its listed 13 kg capacity is the key boundary for heavier tools or equipment.

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

#2 · Side-Access Design

2. STMGW 48-Inch Aluminum Underbody Box

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

Best for: Cam-lock aluminum flatbed storage.

Why it ranks #2: The 48-by-18-by-18-inch aluminum box is specifically described for flatbed truck beds and has double barn doors for side access.

A double barn-door design gives the 48-inch STMGW box side access to stored tools, while its aluminum body keeps the listed weight at 50 pounds. The cam-style lock accepts a separately purchased personal padlock, making this a fit for flatbed owners who prefer that locking arrangement.

The 48 × 18 × 18-inch dimensions provide a large compartment for tools and equipment, and the double barn doors allow access from the side of the truck rather than only through a top lid. Aluminum construction is listed as corrosion-resistant, rust-resistant, and weathertight, supporting under-bed placement. The cam-lock hardware accepts a personal padlock purchased separately, so buyers can use their own lock but must account for sourcing it separately.

Skip it if you want keys included rather than a separate padlock; COOLBAG’s 48-inch steel box includes a T-handle lock and keys.

Consider this for flatbed or truck owners needing a 48-inch aluminum compartment with side-opening barn doors. Its cam lock requires a separate personal padlock, so include that requirement in your access plan.

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

#3 · Black Aluminum Pick

3. FORWODE 36-Inch Aluminum Underbody Box

• Dimensions: 36"L x 17"W x 17.91"H
• Material: Aluminum

Best for: Black aluminum underbody organizer.

Why it ranks #3: This 36-by-17-by-17.91-inch aluminum underbody box mounts below the vehicle, includes two keys, and has a listed 75-pound weight recommendation.

A 36-inch aluminum body gives this FORWODE box a lighter-material alternative for organizing tools under a truck, trailer, or RV. Its foldable T-handle and included keys provide lockable access, while the 36 × 17 × 17.91-inch format offers a substantial compartment without extending to a 48-inch box.

The 36 × 17 × 17.91-inch dimensions create room for tools or camping gear while the underbody mounting position frees cargo area above. Aluminum construction supports a lighter-material choice, and the foldable T-handle provides access to the lockable compartment with two keys included. FORWODE lists a 75-pound maximum weight recommendation, which helps buyers gauge loads; consider the amount of gear and available mounting space when choosing this mid-length box.

Skip it if you need a load recommendation above 75 pounds; VEVOR’s steel tongue box lists a 66-pound limit, so consider Buyers Products’ 3401.64-cubic-inch steel box.

This suits buyers seeking black aluminum underbody storage for tools or camping gear while keeping the cargo area open. Its 36-inch length and 75-pound maximum recommendation are the main fit and load boundaries.

Listed on Amazon as: FORWODE 36x17x18 Inch Underbody Truck Tool Box Aluminum Trailer Tool Box with Lock & Foldable T-Handle Waterproof Truck Storage Box for Pickup Truck, Trailer, RV, ATV, Indoor(BLACK)

#4 · Steel Construction

4. Buyers Products 36-Inch Steel Box

• Dimensions: 36"L x 18"W x 18"H
• Material: Alloy Steel
• Weight: 76 lb
• Capacity: 3401.64 cubic in

Best for: Gasketed steel work-truck storage.

Why it ranks #4: Its 14-gauge steel construction, 36-by-18-by-18-inch dimensions, and locking compression latch suit demanding work-truck and flatbed storage.

A 14-gauge steel body and compression-latch drop door give this 36-inch Buyers Products box a secure underbody storage setup for tools, parts, and supplies. The stainless steel T-handle pulls the door against its gasket, helping control rattling and keep the contents protected during travel.

At 36 × 18 × 18 inches, the box offers a defined storage area for work-truck or flatbed gear without the 48-inch length of larger options. Its 14-gauge steel construction supports demanding applications, while the recessed drop door and stainless compression latch press against the gasket to help limit rattling and weather exposure. A continuous hinge supports the door’s opening, and included keys let owners lock the compartment when equipment is left in the vehicle.

Skip it if you want lighter aluminum storage; VEVOR’s 48-inch aluminum underbody box weighs 37.8 pounds.

This fits buyers seeking a lockable steel compartment for a work truck, flatbed, or trailer, particularly where a gasketed compression door matters. Account for its 76-pound listed weight and 36-inch length when planning installation.

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

#5 · Two-Box Set

5. COOLBAG 48-Inch Steel 2-Pack

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

Best for: Long-bed paired steel storage.

Why it ranks #5: The pair of 48-by-18-by-18-inch steel boxes provides two lockable, weathertight underbody storage units for a flatbed or trailer.

The two-box package pairs 48 × 18 × 18-inch steel storage with lockable, weathertight construction, giving flatbed and trailer owners a way to divide tools or supplies between separate underbody compartments. Its substantial listed dimensions suit buyers who need extended storage space rather than a compact tongue-mounted chest.

Each box uses alloy steel and measures 48 × 18 × 18 inches, providing room for longer tools and bulkier gear than a short tongue box. The lockable T-handle and keys support securing contents between stops, while the weathertight feature suits underbody placement where stored equipment needs protection from the elements. Because this is a two-pack, owners can organize separate categories or mount storage in more than one location, subject to their vehicle’s available mounting space.

Skip it if you need a single narrow tongue-mounted chest; EASYBERG’s 30-inch aluminum box has a smaller listed footprint.

Choose this pair if your flatbed, trailer, pickup, or RV has room for two long underbody boxes and you want lockable, weathertight steel storage. Its 48-inch length makes available mounting space an important consideration.

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

#6

6. Vigorighter 24-Inch Steel 2-Pack

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

Best for: Paired compact steel compartments.

Why it ranks #6: Two 24-by-12-by-14-inch steel boxes are listed for flatbeds and trailers, offering a smaller distributed-storage option with T-handle latches.

Two 24 × 12 × 14-inch steel boxes give this Vigorighter package a way to split tools across compact underbody compartments. Powder-coated sheet steel, fully welded seams, and a locking T-handle support jobsite or travel storage on trucks, RVs, trailers, ATVs, and flatbeds.

Each box measures 24 × 12 × 14 inches, so the pair can separate equipment by task or vehicle location instead of placing everything in one large chest. The alloy-steel construction and rigid powder-coat finish are specified for corrosion resistance, while fully welded seams are described as keeping rain, dust, and grime out. A T-handle latch provides lockable access. The listed maximum recommendation is 20 pounds, an important constraint for heavier tools.

Skip it if you need one long compartment for bulky equipment; COOLBAG’s 48-inch steel box provides a longer storage span.

Choose this pair if you want compact, separately organized storage for lighter tools on a truck, RV, trailer, ATV, or flatbed. The 20-pound maximum recommendation per box rules out heavier loads.

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)

#7

7. COOLBAG 18-Inch Steel 2-Pack

• Dimensions: 18"L x 12"W x 18"H
• Material: Alloy Steel

Best for: Paired short steel storage boxes.

Why it ranks #7: This two-box steel set is listed for flatbeds and trailers and has lockable, weathertight construction, though its compact dimensions limit capacity.

This COOLBAG two-pack pairs compact steel underbody boxes with lockable, weathertight construction, giving trailer and flatbed owners separate spaces for tools or supplies. The 18-inch listed length suits buyers with limited mounting span who want more than one compartment rather than a single long chest.

The alloy-steel boxes have an 18 × 12-inch listed footprint, offering a shorter storage span than the 48-inch COOLBAG pair. Lockable, weathertight features support protected storage under a pickup, trailer, RV, or flatbed, while the two-box package lets owners separate gear by vehicle location or category. The title describes a T-handle lock and keys; plan mounting around the available space and the listed dimensions before deciding where each compartment can go.

Skip it if you need a long compartment for extended tools; STMGW’s 48-inch aluminum box offers substantially more length.

This pair fits buyers who have short mounting spaces and want lockable, weathertight steel storage on a pickup, trailer, RV, or flatbed. Its 18-inch listed length is a limiting factor for long tools.

Listed on Amazon as: 2 Pack Underbody Truck Tool Box, 18"x12"x14" Heavy Duty Steel Storage Chest with T-Handle Lock & Keys, Waterproof Under Mount Toolbox Organizer for Pickup, Trailer, RV, Flatbed, Powder Coated

#8

8. Buyers Products 72-Inch Contractor Box

• Dimensions: 72"L x 13.5"W x 21"H
• Material: Aluminum
• Weight: 58 lb
• Capacity: 383 liters

Best for: Organized contractor tool storage.

Why it ranks #8: Its 72-inch aluminum format offers a large upper compartment and two divided drawers, but it is a contractor box rather than a dedicated underbody design.

Two lower drawers with adjustable dividers distinguish this 72-inch Buyers Products contractor box, letting crews separate small parts from bulky tools in a single storage unit. A large flip-up upper compartment adds room for larger supplies, while black diamond-tread aluminum provides a corrosion-resistant format for pickup and utility-body use.

The 72 × 13.5 × 21-inch dimensions create a long, relatively shallow storage profile, and the two-tier arrangement supports distinct workflows: bulky gear goes in the upper compartment while frequently used parts can be divided among the lower drawers. Its .056-inch aluminum construction is described as corrosion-resistant, a useful property for work-vehicle storage. Mounting hardware is included, but buyers should account for the listed 100-pound maximum recommendation when loading the compartment.

Skip it if you need an underbody box with a higher listed load recommendation; Vigorighter’s two steel boxes list 20 pounds each.

This suits contractors and fleet operators who value separated storage for bulky tools and small parts in a long truck-mounted box. Check the 100-pound maximum recommendation and the 72-inch footprint against your vehicle and load.

Listed on Amazon as: Buyers Products 1725641 72 Inch Black Aluminum Contractor Tool Box

#9

9. VEVOR 36-Inch Steel Tongue Box

• Dimensions: 36"L x 12"W x 12"H
• Material: Steel
• Weight: 28.4 lb
• Capacity: 66 lb

Best for: Compact steel tongue-box organizer.

Why it ranks #9: The 36-by-12-by-12-inch steel box includes two keys, but its trailer-tongue placement makes it less suited to underbody flatbed storage.

A 36 × 12 × 12-inch footprint makes this VEVOR carbon-steel tongue box a narrower option for keeping tools and equipment on a trailer. It provides lock-and-key storage with a listed 66-pound maximum load, giving buyers a defined compartment for essentials without choosing a wide underbody chest.

The compact 36 × 12 × 12-inch shape is intended for mounting on a trailer tongue, where it can keep tools and outdoor equipment accessible during trips. Carbon steel and a double-sided dusting finish support a sturdy exterior, while the lock and two keys provide secured access. The 66-pound maximum weight recommendation gives a clear limit for loading; this is better suited to essential gear than buyers needing a high-capacity tool chest.

Skip it if you need a longer underbody compartment; STMGW’s 48-inch aluminum box offers more length for tools and equipment.

This suits trailer owners who want a compact, lockable tongue compartment for essential tools or outdoor gear. Keep the 66-pound maximum load in mind, and make sure the 36-inch length fits the intended tongue location.

Listed on Amazon as: VEVOR Trailer Tongue Box, Heavy Duty Trailer Tongue Tool Box Storage Organizer with Lock & Keys, Utility Tool Chest for Pickup Truck Bed, RV, SUV, Off-Road Vehicle, Steel, 36" x 12" x 12"

#10

10. EASYBERG 30-Inch Aluminum Tongue Box

• Dimensions: 30"L x 13"W x 13"H
• Material: Aluminum
• Capacity: 83.08 liters

Best for: Aluminum tongue-box access.

Why it ranks #10: Its 30-by-13-by-13-inch aluminum body, gas-strut lid, and lock suit tongue mounting, not the underbody flatbed use sought here.

A gas-strut lid gives this 30-inch EASYBERG tongue box a practical access feature, holding the lid open while you reach tools, straps, or accessories. Its aluminum body and 5-bar tread pattern offer a corrosion-resistant option for trailer storage where a compact, lockable compartment is preferable to a long underbody box.

The 30 × 13 × 13-inch dimensions make this box suitable for buyers organizing smaller trailer essentials while conserving available space. Aluminum construction with 1.5 mm material and fully welded seams supports outdoor use, and the 5-bar tread pattern adds a textured exterior. A gas strut assists lid access, while the lockable design and two keys help secure contents; the listed 83.08-liter capacity provides a useful measure for planning what to store.

Skip it if you need a 36-inch tongue compartment; VEVOR’s 36 × 12 × 12-inch steel tongue box is longer.

Pick this for trailer owners who want an aluminum tongue box with assisted lid access for straps, tools, and smaller gear. Its 30-inch length is a space-conscious format, not the longest option in this group.

Listed on Amazon as: 30" Aluminum Trailer Tongue Tool Box with Lock & 2 Keys, Silver