Best Tool Box For Flatbed Trailer: 10 Options Compared

#1 · Best Overall

1. Buyers Products 1702305

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

Best for: Heavy-duty steel flatbed storage.

Why it ranks #1: Its 36 x 18 x 18-inch steel body is listed for flatbed and underbody storage, with 14-gauge construction and a locking compression latch.

Its 14-gauge steel body gives this 36-by-18-by-18-inch Buyers Products box a substantial enclosure for tools and supplies carried under a work truck or flatbed. A stainless steel compression T-handle pulls the recessed drop door against its gasket, helping secure contents and reduce rattling while the vehicle is moving.

The 36-inch length and 18-inch height provide a defined storage space for work tools, parts, and supplies, while the 14-gauge steel construction suits demanding truck and trailer use. Its recessed drop door gives access through the front, and the locking stainless steel compression latch draws that door against the gasket to help limit rattling and exposure to weather. The black powder-coated finish is described as corrosion resistant; the 76-pound weight is worth factoring into handling and installation.

Skip it if you need a lighter aluminum enclosure; the 28.4-pound VEVOR UTTB-361718 is a smaller, lighter alternative.

For flatbed and work-truck owners who prioritize a steel enclosure, a locking compression latch, and a gasketed drop door, this Buyers Products box offers a substantial storage option. Account for its 76-pound 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

#2 · Best Barn Doors

2. Buyers Products 1702235

• Dimensions: 24"L x 24"W x 36"H
• Weight: 63 lb
• Material: Aluminum

Best for: Wide-access aluminum trailer storage.

Why it ranks #2: The 24 x 24 x 36-inch aluminum box is explicitly intended for flatbeds and trailers, with barn doors, a rain gutter, and a compression latch.

Two side-hinged barn doors provide this Buyers Products box with a wide-opening access point, enabling easier retrieval of stored gear than a narrow opening. Its 24-by-24-by-36-inch aluminum enclosure uses .100-inch diamond tread material, a rain gutter, and a bulb seal for weather-conscious flatbed and trailer storage.

The 36-inch dimension and barn-door opening give users access to a sizable interior without lifting a single top lid, a practical arrangement when retrieving tools beside a work truck or trailer. The .100-inch diamond tread aluminum is specified for strength and corrosion resistance, while a rain gutter and bulb seal help keep rain and dust away from contents. A locking die-cast compression latch and continuous hinge with a 1/4-inch pin add security. At 63 pounds, it still requires planning for handling.

Skip it if you need a lightweight, low-profile tongue box; FGJQEFG WJ1090 is aluminum, 19.8 pounds, and 12.3 inches high.

For flatbed users who value wide access and weather-sealing features, this Buyers Products aluminum box offers a distinct barn-door arrangement. Check the 24-by-24-by-36-inch dimensions against the intended mounting space and allow for its 63-pound handling weight.

Listed on Amazon as: Buyers Products 1702235 Underbody Truck Tool Box with Barn Doors, 24x24x36 Inch, Diamond Tread Aluminum, Made in USA, Compression Latch, Weather Resistant, Toolbox for Flatbeds, Trailers & Work Trucks

#3 · Best Step Box

3. Mytee Products Step Box

• Dimensions: 28.4"L x 24.5"W x 18"H
• Weight: 40 lb
• Material: Aluminum

Best for: Step-access flatbed tool storage.

Why it ranks #3: This flatbed-trailer side-mount box combines a .125-inch aluminum body, open-wide access, a rubber seal, and punch-plate steps.

Punch-plate saddle steps paired with an open-wide lid make the Mytee Products box both a storage compartment and a step-access design, enabling easier access to gear on a semi or flatbed. Its .125-inch smooth aluminum body and lid combine sturdy construction with a rubber seal for weather resistance.

The 24.5-inch height, 28.4-inch depth, and 18-inch width define a saddle-mounted form that can provide storage alongside step access. Punch-plate steps and the open-wide lid support reaching the contents, while T-locks secure the box. Mytee Products specifies a .125-inch smooth aluminum body and lid, plus a rubber seal to resist weather. At 40 pounds and 13,500 cubic inches of stated capacity, it balances substantial storage with a specific step-box arrangement.

Skip it if you need a wider underbody box rather than saddle-step storage; Buyers Products 1702305 is 36 inches wide.

This Mytee Products box fits semi-truck and flatbed owners who want storage combined with saddle-step access and an open-wide lid. Its 24.5-by-28.4-by-18-inch dimensions and step-box arrangement should suit the available mounting location.

Listed on Amazon as: Mytee Products 24.5"x28.4"x18" Aluminum Side Mount Semi Truck Tool Box with Saddle Step Open Wide Design & T-Handle Latch Lock – Heavy Duty Weather Tight Step Tool Box for Flatbed Trailer

#4 · Lightest Listed

4. VEVOR 36-Inch Underbody Box

• Dimensions: 36"L x 17"W x 18"H
• Weight: 28.4 lb
• Material: Aluminum

Best for: Flexible aluminum trailer storage.

Why it ranks #4: Its 36 x 17 x 18-inch aluminum body weighs 28.4 pounds and includes a rubber sealing strip, lock, and two keys.

The VEVOR box can be installed beneath a truck or trailer or placed on a camper back or pickup rack, enabling storage beyond one mounting position. Its 36-by-17-by-18-inch aluminum body includes a rubber sealing strip and a lock with keys, combining adaptable placement with protection for stored equipment.

At 28.4 pounds, this aluminum box is comparatively manageable to position, and its listed dimensions help owners assess whether it suits an underbody, camper, or rack location. The rubber sealing strip creates a tight seal when closed, supporting the stated waterproof protection against incoming water. A T-handle latch and two keys provide a way to lock the contents. The listed maximum weight recommendation is 88 pounds, so the box is not intended for loads beyond that stated limit.

Skip it if you need a much longer steel enclosure; COOLBAG CB1188 measures 48 inches long and is supplied as a two-box set.

This VEVOR fits owners seeking aluminum storage that can serve an underbody, camper, or pickup-rack location. Its 88-pound maximum weight recommendation is a clear boundary, and the 36-by-17-by-18-inch size still needs to suit the chosen mounting space.

Listed on Amazon as: VEVOR Underbody Truck Box, 36"×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

#5 · Longest Listed

5. BIGREAT 60-Inch Steel Box

• Dimensions: 61.4"L x 20.9"W x 20.5"H
• Weight: 104.5 lb
• Material: Steel

Best for: Long steel underbody storage.

Why it ranks #5: The 60-inch steel underbody model offers a wide format, hand-welded seams, powder-coated 14-gauge steel, and a lockable latch.

At 60 inches long, the BIGREAT steel underbody box provides an extended storage footprint for flatbed and trailer equipment, enabling longer tools and supplies to be kept together. Its powder-coated 14-gauge steel construction and hand-welded seams are specified for a sturdy, corrosion-resistant enclosure.

The 60-by-18-by-18-inch overall size gives this box a notably long storage area, which can help keep work gear organized without dividing it among shorter containers. BIGREAT specifies 14-gauge steel with hand-welded seams for strength, and a powder-coated surface intended to resist corrosion and weather exposure. The stated lockable feature supports securing stored equipment. At 104.5 pounds, the box is heavy to move, so its weight matters when arranging installation and handling.

Skip it if you need a lighter long aluminum box; HEVIKE XT0179 is 48 inches long and listed at 50 pounds.

This BIGREAT suits flatbed and trailer owners who want a long steel enclosure for grouped tools and supplies. Its 60-inch length and 104.5-pound listed weight should both be considered when planning available underbody space and installation.

Listed on Amazon as: 60'' Inch Steel Underbody Truck Tool Box & T-Handle Latch

#6

6. HEVIKE 48-Inch Barn Door Box

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

Best for: Easy-access aluminum barn doors.

Why it ranks #6: This 48 x 18 x 18-inch aluminum side-mount box is listed for trailers, semis, and flatbeds, with double barn doors and a cam lock.

Its double barn-door layout gives the HEVIKE box an easy-opening access style for side-mounted trailer and flatbed storage, while the 48-by-18-by-18-inch dimensions define a substantial equipment compartment. Aluminum construction and a smooth, non-mirror finish support corrosion resistance and easier routine cleaning.

The double barn doors open for access to stored equipment, while the listed cam lock provides a way to secure the compartment. HEVIKE specifies aluminum for corrosion resistance and says the smooth surface is easier to clean and maintain in daily use. The 48-by-18-by-18-inch format offers a broad storage footprint for commercial vehicle equipment; its 50-pound weight is a planning factor when mounting. A powder coating is also described as helping block rain and resist corrosion during outdoor use.

Skip it if you need a compact, lightweight tongue box rather than a 48-inch side-mount box; FGJQEFG WJ1090 weighs 19.8 pounds.

HEVIKE’s box suits flatbed and trailer owners who prefer double-door access, a cam lock, and an aluminum enclosure with a cleanable surface. Consider the 48-by-18-by-18-inch footprint and 50-pound weight when choosing a mounting position.

Listed on Amazon as: Heavu Duty Aluminum Underbody Truck Tool Box With Cam Lock, Double Barn Door, 48"×18"×18" Side Mount Tool Box for Trailer, Semi Truck, Flatbed Truck

#7

7. FGJQEFG 48-Inch Steel Box

• Dimensions: 48"L x 18"W x 18"H
• Weight: 69.1 lb
• Material: Steel

Best for: Lockable 48-inch steel storage.

Why it ranks #7: The 48 x 18 x 18-inch steel underbody box is described for truck trailers and outdoor use, with a lock and key.

A 48-by-18-by-18-inch steel enclosure gives this FGJQEFG box a straightforward underbed storage footprint for trailers, pickups, and RVs. Its lock and key are listed alongside waterproof and corrosion-resistant steel, enabling owners to secure outdoor equipment in a box sized for underbody use.

The 48-inch length and 18-inch height provide room for tools and equipment while giving buyers defined dimensions for planning a trailer or truck installation. FGJQEFG lists steel with waterproof and corrosion-resistant properties, supporting use in outdoor vehicle settings. A lock and key address the security of stored items, while the box’s 69.1-pound listed weight is a handling consideration during placement. The information identifies the material and locking feature but does not specify an opening style or detailed seal design.

Skip it if you want aluminum with a low-profile tongue-box shape; FGJQEFG WJ1090 is 39.3 inches long and 12.3 inches high.

This FGJQEFG box suits buyers looking for a lockable 48-inch steel enclosure for outdoor truck, trailer, pickup, or RV storage. Its 69.1-pound weight and 18-inch height are important practical considerations for handling and available mounting clearance.

Listed on Amazon as: 48'' Heavy Duty Truck Tool Box Steel for UnderBed Trailer Outdoor Car with Lock and Key – 48 x 18 x 18 Inch Black Underbody Toolbox

#8

8. higehio 48-Inch Aluminum Box

• Dimensions: 48"L x 17.5"W x 19.5"H
• Material: Aluminum

Best for: Tread-pattern aluminum truck storage.

Why it ranks #8: Its 48-inch aluminum body has a reinforced 5-bar tread pattern and a black powder-coated finish, though the listing gives fewer fit details.

A reinforced five-bar tread pattern gives this higehio aluminum box added structural strength while creating a distinct exterior for trailer or truck storage. Its 48-by-17.5-by-19.5-inch dimensions and black powder-coated finish provide a substantial, corrosion-resistant enclosure for tools kept in outdoor conditions.

The 48-inch length offers a broad storage footprint, while the 17.5-inch width and 19.5-inch height help buyers assess its fit against available mounting space. Higehio specifies 1.5-millimeter aluminum and a reinforced five-bar tread pattern, linking the lightweight material to added structural strength. The black powder coating and stated waterproof, corrosion-resistant performance address outdoor exposure. A lockable feature is listed, but the supplied details do not specify the lock mechanism or an included key.

Skip it if you want barn-door access with a specified cam lock; HEVIKE XT0179 lists double barn doors and a cam lock.

This higehio box suits buyers who want a tread-pattern aluminum enclosure for truck or trailer tool storage and value a powder-coated finish. Check the 48-by-17.5-by-19.5-inch dimensions and note that lock details are not specified.

Listed on Amazon as: Aluminum Truck Tool Box 5 Bar Tread Trailer Tool Box,48×19.5×17.5

#9

9. COOLBAG 48-Inch Box Set

• Dimensions: 48"L x 14"W x 16"H
• Material: Alloy Steel

Best for: Two-box trailer storage setup.

Why it ranks #9: The listing describes steel underbody storage for trailers and flatbeds with T-handle locks, but product dimensions are given for a two-box set.

The two-box package gives flatbed and trailer owners a pair of 48-by-14-by-16-inch steel storage chests, enabling storage to be split between locations rather than concentrated in one enclosure. COOLBAG lists T-handle locks and keys, with a weathertight, waterproof description for outdoor vehicle use.

Each chest measures 48 inches long, 14 inches wide, and 16 inches high, dimensions that can help owners plan placement and organize tools across two storage points. The steel construction provides a rigid enclosure, while the listed T-handle lock and keys support securing contents. COOLBAG describes the boxes as waterproof and weathertight, a useful feature for trailer and RV equipment exposed to outdoor conditions. The 14-inch width is a practical constraint when storing bulky gear.

Skip it if you need a wider steel box for bulky tools; BIGREAT BR0230 measures 18 inches wide and 60 inches long.

Choose this COOLBAG set if your flatbed or trailer setup benefits from dividing equipment between two steel boxes. Its 14-inch width is a key fit consideration, especially for bulky tools, and the listing identifies a weathertight, lockable configuration.

Listed on Amazon as: 2 Pack Underbody Truck Tool Box, 48"x14"x16" Heavy Duty Steel Storage Chest with T-Handle Lock & Keys, Waterproof Under Mount Toolbox Organizer for Pickup, Trailer, RV, Flatbed, Powder Coated

#10

10. FGJQEFG Tongue Box

• Dimensions: 39.3"L x 16.8"W x 12.3"H
• Weight: 19.8 lb
• Material: Aluminum

Best for: Lightweight trailer tongue storage.

Why it ranks #10: This 39-inch aluminum box is designed for a utility trailer tongue, making it less directly suited to general flatbed underbody mounting.

Weighing 19.8 pounds, this 39-inch aluminum utility box offers trailer owners a lightweight tongue-storage option that limits added box weight. Its overlapping lid and seal-ring design are described as helping prevent leakage and keep the interior clean, supporting storage of gear exposed to outdoor conditions.

The 39.3-by-16.8-by-12.3-inch dimensions give this box a low, elongated profile for buyers evaluating tongue or trailer storage space. Aluminum construction combines a lightweight form with the listed corrosion resistance, while the overlapping lid is described as preventing leakage and the seal ring helps keep rainwater out. The listed maximum weight recommendation is 75 pounds, which sets a clear load boundary. Its compact height may suit smaller equipment better than tall tools.

Skip it if you need a taller enclosure for larger tools; BIGREAT BR0230 is 18 inches high and 60 inches long.

This FGJQEFG box is a fit for trailer owners seeking lightweight, low-profile tongue storage with a sealing lid arrangement. The 12.3-inch height and 75-pound maximum weight recommendation define its practical limits for tool size and load.

Listed on Amazon as: 39'' Inch Aluminum Utility Trailer Tongue Tool Box(39"X16.5"X12")