Finding the right side or underbody box for a flatbed means balancing security, weather resistance, and ease of access. This guide highlights five strong options across steel and aluminum, suitable for contractors, fleet operators, and DIY enthusiasts. Each pick prioritizes durability, theft deterrence, and underbody mounting compatibility while explaining who benefits most and any practical limits.
Product Comparison Summary
| Product | Size / Type | Material | Best For | Why Pick |
|---|---|---|---|---|
| Buyers Products 1702315 | 18 x 18 x 60 in | Steel | Heavy-use fleets | Rugged steel with weather sealing and secure latch |
| 1762645 Buyers Aluminum Box | 24 x 24 x 60 in | Aluminum | Flatbeds needing lighter weight | Cam-lock hardware and universal install |
| FORWODE 36x17x18 Aluminum Box | 36 x 17 x 18 in | Aluminum | Mid-size pickups and trailers | Fully weatherproof with flush folding handle |
| 60 Inch CaQeg Top Box | 60 in x 21 in x 13.5 in | Aluminum | Tall payloads and organized storage | One large swing-up door, weather-sealed |
| FGJQEFG 48” Steel Box | 48 x 18 x 18 in | Steel | Outdoor trailer and pickup use | Durable steel with basic waterproofing |
Buyers Products 1702315 Black Steel Underbody Truck Tool Box
Material and construction emphasize durability for harsh job sites. Best for fleets or contractors needing a large underbody toolbox with secure locking. The 14-gauge steel body, corrosion-resistant powder coat, and a stainless steel compression latch provide robust theft protection and moisture control. A recessed drop door and continuous hinge seal out dust and debris, making it a solid all-weather option. Avoid this if you require the lightest possible option or need a non-steel alternative for weight-sensitive installations.
HEVIKE Heavu Duty Aluminum Underbody Box
Best for users prioritizing lighter weight without sacrificing strength. The aluminum construction offers corrosion resistance and a smooth surface for easy cleaning. Non-mirror barn doors reduce glare and fingerprint marks. The cam lock is compatible with personal padlocks, providing an extra layer of security. Choose this if you want easier handling and padlock-ready security; avoid if you require steel-level scratch resistance or maximum load tolerance beyond aluminum’s capacity.
Buyers 1762645 Smooth Aluminum Underbody Box
Best for flatbeds needing universal mounting and lighter weight than steel counterparts. The 0.125-inch-thick smooth aluminum shell offers corrosion resistance and a sleek profile. Cam-lock hardware accepts personal padlocks, enhancing theft deterrence. It supports mounting on either driver or passenger side for flexible layout. Limitations include a potentially lower impact resistance compared with heavier steel models and a higher cost compared to basic steel boxes.
FORWODE 36x17x18 Aluminum Underbody Box
Best for users needing a compact underbody storage solution with weatherproof protection. This box mounts underneath to free cargo space, provides a tight seal with rubber gaskets, and uses a flush folding T-handle for snag-free travel. The built-in lock adds theft deterrence. Choose this if you need a space-saving design for smaller flatbeds; avoid if you require a larger capacity box for heavy-duty tools.
60 Inch Contractor Top Side Box With Two Lower Drawers
Best for taller trucks and organized tool storage. The Topsider design provides a large swing-up door to maximize access, especially on higher-profile beds. Made from aluminum with a weather-sealed construction, it is suitable for long-term outdoor use. Choose this if you need maximum storage area and easy reach; consider weight and installation space if your truck bed is compact or the trailer is already loaded.
Buyers 1703353 Black Steel Underbody Box
Best for demanding environments where steel construction is preferred. The 14-gauge steel body with corrosion-resistant powder coat provides robust protection against environmental exposure. The stainless steel compression latch and recessed drop door deliver theft deterrence while protecting contents from moisture. Choose this for heavy-duty durability; it may be heavier and more cumbersome to install than aluminum options.
Buying Guide: Key Purchase Considerations
- Material choice: Steel boxes offer maximum durability and security; aluminum boxes reduce weight and resist corrosion for lighter setups and longer life in salty or humid environments.
- Mounting style: Underbody boxes save cargo space but require proper mounting; top-side or dual-door designs can improve access for taller loads.
- Security features: Look for lockable latches, padlock compatibility, and gasketed doors to keep out dust, moisture, and theft.
- Weather protection: Rubber seals, continuous hinges, and powder-coated finishes enhance all-weather performance.
- Installation flexibility: Universal mounting and reversible side access help fit a wider range of flatbeds and trailers.
- Maintenance: Aluminum boxes are generally easier to clean and resist corrosion; steel boxes may require rust protection in harsh environments.
Frequently Asked Questions
- What is the best material for an underbody tool box?
– It depends on your priorities: steel for ultimate durability and security; aluminum for lighter weight and corrosion resistance. - Do underbody boxes fit all flatbeds?
– Most underbody boxes are designed for universal mounting, but check your truck bed’s dimensions and mounting points before purchase. - Are padlocks necessary with Cam-Lock hardware?
– Cam-Lock systems can work with personal padlocks for added security; verify compatibility in product specs. - What maintenance is required for aluminum boxes?
– Regular cleaning to remove grime and periodic coating checks protect against corrosion in harsh environments. - How do I choose between a single-door and double-door design?
– Double-door or swing-up designs offer easier access for taller loads, while single-door boxes maximize compact space.