How REV’s Mega Box Storage Actually Expands Your Truck Bed
Most truck owners install a tonneau cover for security and weather protection, then realize they’ve created a new problem: where do you stash the smaller gear that used to ride loose in the bed? Straps, tools, recovery gear, and tie-downs end up sliding around under the cover or piled against the cab, wasting the very space you wanted to protect.
REV’s Mega Box solves this by turning the dead space behind your bulkhead into a lockable, weatherproof tonneau cover storage box that mounts directly to the bed rail. You gain 15 cubic feet of organized storage without losing an inch of usable bed length, and the box works seamlessly with our hard folding covers so you can still haul plywood, bikes, or anything else that needs the full bed.
Why the Space Behind Your Bulkhead Sits Empty
Every pickup has a vertical bulkhead separating the cab from the bed, and that creates a triangular wedge of space that’s too narrow for cargo but wide enough to frustrate you every time you load something. Most drivers ignore it or toss a duffel bag back there, knowing it won’t slide forward.
The Mega Box was designed specifically for that wedge. It mounts to the bed rail with clamps identical to those on our Mega Box for Hard Folding Tonneau Cover by REV, so installation takes about ten minutes and requires no drilling. The box sits flush against the bulkhead and extends only as far forward as necessary, leaving the rest of your bed length untouched.
Because it’s elevated on the rail, you can still slide longer cargo underneath when the tonneau is folded open. That keeps your bed versatile instead of turning it into a fixed trunk.
What Actually Fits Inside a Bed-Mounted Storage Box
Fifteen cubic feet sounds abstract until you start loading. The Mega Box holds two full-size floor jacks side by side, or a full socket set, jumper cables, a tow strap, and a toolbox with room left over. We’ve seen customers fit a week’s worth of camping gear, a compressor and air hose, or an entire detailing kit with space to spare.
The interior is a single open cavity with no dividers, so you decide how to organize it. Some owners drop in a small bin for fasteners and another for electrical supplies; others load it like a duffel and rely on the lockable lid to keep everything secure.
The key advantage over a traditional toolbox is that the Mega Box doesn’t steal bed floor space. You’re borrowing vertical real estate that was doing nothing, so a sheet of plywood or a motorcycle still fits exactly as it did before.
How the Mega Box Integrates with a Hard Folding Cover
A tonneau cover storage box only makes sense if it doesn’t interfere with the cover’s operation. The Mega Box was engineered alongside our hard folding panels, so when you fold the cover open, the panels stack behind the box instead of hitting it.
That means full bed access in under ten seconds. Flip the first panel back, then the second, and the third stacks neatly against the Mega Box without blocking your view or limiting how far the panels open. The box actually acts as a natural stop, so the panels don’t flop past vertical and stress the hinges.
If you’re comparing folding styles and wondering whether a box will work with your setup, our REV Hard Folding vs Hard Rolling Tonneau Cover guide walks through how each design handles bulkhead clearance and storage accessories. Rolling covers require different box placement since the canister sits at the front, but folding covers leave that wedge wide open.
Weatherproofing and Security Features
The Mega Box uses the same rotomolded polyethylene shell as high-end coolers, so it’s genuinely waterproof rather than water-resistant. The lid compresses a continuous rubber gasket when you turn the latch, creating a seal tight enough that we’ve seen customers submerge the box during pressure-washing with zero water intrusion.
Locking is handled by a keyed paddle latch that matches the tonneau cover’s lock cylinder. You can key them alike so one key opens both the cover and the box, or run separate keys if multiple people access the truck. The latch sits recessed in the lid, so it’s not easy to pry or hammer off without destroying the entire box.
UV stabilizers in the polymer keep the shell from chalking or cracking even in desert sun. We’ve had test units in Arizona and Texas for three years with no fade or brittleness, which matters when your storage box is exposed 24/7 instead of tucked under a cover.
Installation on Different Truck Models
The Mega Box clamps to any truck bed rail with a T-slot or stake pocket, which covers nearly every full-size pickup built since 2015. The clamps slide into the rail channel and tighten with a hex bolt, so you’re mechanically locked in rather than relying on adhesive or straps.
Bed width varies between makes, but the Mega Box is sized to fit the narrowest common bed (around 50 inches between the rails) while still maximizing volume. That means it fits a REV Hard Folding Tonneau Cover for GMC as easily as it fits an F-150 or a Ram, with no modification.
If you have a short bed (5.5 feet), the box takes up a slightly larger percentage of your length, but you still retain over four feet of open bed floor. Long bed owners (eight feet) barely notice it. The box’s footprint stays constant across all bed lengths, so the trade-off is predictable.
Turning Wasted Space Into Usable Storage
The wedge behind your bulkhead exists on every truck, and most owners never do anything with it beyond tossing a bag back there and hoping it stays put. A purpose-built storage box like the Mega Box turns that dead zone into 15 cubic feet of lockable, weatherproof space without sacrificing bed length or interfering with your tonneau cover.
If you haul gear regularly and you’re tired of everything sliding around under the cover, a bed-mounted box is the simplest fix. It keeps small items organized, protects them from weather and theft, and leaves your bed floor open for the bulky cargo you actually bought the truck to carry.
Common Questions About Truck Bed Storage Boxes
Yes. The box clamps to the bed rail independently of the cover, so you can unbolt the four clamps and lift it out in under five minutes. The tonneau cover stays in place and functions normally with or without the box installed.
Most owners leave the box mounted year-round since it doesn’t interfere with hauling, but seasonal users appreciate the quick-release design.
The Mega Box itself weighs 35 pounds empty, and its rated load capacity is 150 pounds. Your truck’s payload rating accounts for all added weight, including the cover, the box, and whatever you load inside it.
For perspective, 35 pounds is less than a full tank of gas. If you’re hauling near your truck’s max payload regularly, account for the box’s weight, but for typical use it’s negligible.
No. The Mega Box mounts behind the bulkhead, and fifth-wheel hitch plates sit in the center of the bed floor, so the two don’t overlap. Gooseneck ball mounts also clear the box since they’re positioned forward of the rear axle.
Some puck-style hitches have rails that run along the bed floor, and those can pass under the Mega Box without issue since the box is elevated on the bed rail.
The polyethylene shell accepts vinyl wrap well if you use a primer designed for plastics. Some customers have color-matched the box to their truck using automotive vinyl, and it holds up as long as the wrap is applied correctly.
Paint is trickier since polyethylene flexes and most paints will crack over time. If you want a permanent color change, a professional wrap is the better route.
The Mega Box ships as a single open cavity with no dividers, so you can configure it however you want. Some owners install aftermarket drawer organizers or drop in plastic bins; others use tie-down straps along the interior walls to secure larger items.
We intentionally left it open because everyone’s gear is different, and fixed dividers often create compartments that are too small or too large for what you actually carry.
The rotomolded polyethylene stays flexible down to minus 40 degrees Fahrenheit and won’t warp in heat up to 180 degrees, so it handles anything a truck bed sees in normal use. The gasket remains pliable across that range, so the weatherproof seal doesn’t fail in winter.
If you live somewhere with extreme temperature swings, the box won’t crack, fade, or lose its seal the way cheaper injection-molded boxes often do.