UnderCover Flex Detailed Review

The UnderCover Flex is a basic hardshell tri-fold cover that is available for a variety of truck models. It does not go hard on the pocket and offers all the features a normal hardcover offers. It is a smart pick, that stands up to the demands of regular use.

UnderCover Flex Truckbed Cover
UnderCover Flex Tonneau Cover

Good Points

  • Fiberglass-reinforced Polymer coating
  • Low profile flushed look
  • Lock Rod to fix the panel at 2/3 position


  • Water seeps into the truckbed
  • FRP layer may get cracks
  • Some components may wear out, potentially requiring replacement
  • The color may begin to fade and the initial shine could diminish over time.

Have a look at the specs.

MaterialHigh-quality aluminum panels with an FRP top layer
FinishGlossy textured black finish, resistant to UV rays and scratches
DesignTri-fold, Low profile design
Weight CapacityApproximately 300-400 lbs (evenly distributed weight)
Product WeightApproximately 50-70 lbs, based on the truck bed size
Locking MechanismSlam latch system operable from either side with pull cables
Opening PositionsThree secure positions: fully closed, partially open (midway), fully open with prop rods
SecurityCannot be opened without opening the tailgate
Weather ResistanceEPDM rubber seals and a water-tight channel drainage system
InstallationNo-drill, user-friendly installation with clamp-on rails
Added FeaturesBuckle straps and lock-rod to lock 3rd panel to fold in the partially open position
Warranty3 years
Table of specifications – UnderCover Flex

Structure and Built

The UnderCover Flex tonneau cover has a tri-fold design that’s all about function. It has a low profile and sits flush with the truck bed, giving it a clean, low-profile look. The cover is sturdy, made with aluminum panels that are strong but not heavy, making it easy to handle.

The top surface of the cover is made of called Fiberglass Reinforced Polymer (FRP). It’s got a texture that looks good and doesn’t show scratches easily, which is great for daily use. The black finish stays looking new for a long time.

Moreover, the UnderCover Flex tonneau cover features a durable coating that’s both UV-resistant and corrosion-resistant. This doesn’t let the cover lose its color under the sun or in the face of salt and moisture, which can be a real concern in coastal areas or places with snowy winters.

UnderCover Flex
UnderCover Flex On Ford F-150

When it comes to durability, the Flex is solid. It can handle 300 to 350 lbs of equally distributed weight on top without bending, and it doesn’t get dented easily if you accidentally knock something against it. It’s also built to keep water out. I’ve driven through some serious rain, and the stuff in the truck bed stayed dry.

Furthermore, the cover features EPDM seals to resist water and has a water drainage system to direct water away from the drain tubes.

For locking and unlocking the cover uses a secure latching system. The cover is unlocked with a pull cord system and can only be unlocked after unlocking the tailgate. It features a lock rod at the third panel to secure the panels at 2/3 position and buckle straps are provided to further secure the panels in this position.

For full bed access, the cover can be held with the help of prop rods at a vertical position, away from the cabin window. So, you do not need to

Installing the Flex cover is pretty simple, too. There’s no need to drill or do anything intense. It clamps on, and you can do it by yourself, without needing to call in any favors.

Overall, the UnderCover Flex feels like a reliable cover. It does its job of protecting your gear without making your truck look bulky. It’s easy to use, holds up well, and blends in with the truck’s design.

Installation and Easy Operation

The UnderCover Flex tonneau cover is pretty user-friendly. It is very easy to install this cover. It’s a clamp-on system, so there’s no drilling required.

You can mount it onto your truck bed rails without any specialized tools. The instructions on the provided manual are clear, and if you do need a hand, there’s always customer service to walk you through it.

Once it’s installed, using the cover is straightforward. Opening and closing it doesn’t require any heavy lifting. The panels are lightweight, and they fold up against the back window when you need to haul something big.

One thing I would like to mention is you may need a hand while mounting it because it is heavy, for me it was.

As for aerodynamics, having the UnderCoverFlex cover on your truck helps smooth out the airflow over the bed. This means less air drag, which can lead to better fuel efficiency.

The cover snaps into place securely, and it doesn’t flap around or make a fuss when you’re driving. Plus, it gives your truck a sleek look, enhancing the overall driving experience by reducing wind noise at higher speeds.

If you need to haul taller items that require the whole bed, the UnderCover Flex tonneau cover has these handy prop rods that keep it upright and out of the way.

I’ve had my UnderCover Flex cover for three years, and it’s served me well. It did not stay as shiny as when it first arrived, it’s lost a bit of that new-cover gloss over time.

That’s why I didn’t put it on my list of best tri-fold hard tonneau covers. Click here to see the list.

Also, I noticed a small crack on the FRP coat on one of the panels, even though I’ve been careful not to overload it. This makes me wonder about its UV-resistance capability, although the rest of the cover has held up pretty well.

Throughout the time I’ve had it, the seals have remained intact. I haven’t had any problems with water getting into the truck bed on a normal rainy day.

UnderCover Flex Fibreglassa Reinforced polymer coating
UnderCover Flex Tonneau Cover FRP Top

However, I’ve got to say, that experiences can vary. My neighbor picked up the same cover and ended up with some leakage issues. Luckily, the warranty covered a replacement for him.

Some folks think it’s excellent, while others have run into problems. From my perspective, it’s a solid cover that fulfills, what you expect from a basic hard tonneau cover.

It was the first one I ever owned, and it definitely impressed me at that time. Kept it for three years, which says something about its longevity and performance.

Check out its successors, UnderCover Ultra Flex and Armor Flex for even cooler features and stronger protection.

Now, if it’s just a quick grab you need to make, you don’t have to fold the cover back every time. Just flip open the panel nearest the tailgate, and you’re in. Plus, the latches are on both sides, so it doesn’t matter where you are around the truck, you can get to your gear.

The UnderCover Flex is designed to stay securely in place. Once it’s closed and your tailgate is locked, your stuff is secure. You can drive around knowing that whatever you’ve got in the back isn’t going anywhere, and it’ll stay dry too, thanks to the water-tight seals.

Maintaining the Flex cover is simple because it does not really need any. Its surface is easy to clean; just a quick wipe-down with some soap and water does the trick.

The FRP material is durable and resistant to the elements, so it doesn’t need special treatment. The simplicity of its maintenance means more time using your truck and less time worrying about upkeep.

In a nutshell, the UnderCover Flex is about as hassle-free as a tonneau cover gets. It’s low-maintenance, doesn’t demand any special tools or knowledge to use, and it’s reliable and a solid choice if you want protection without the fuss.


The UnderCover Flex tonneau cover is designed to perform well in a variety of challenging weather conditions


Its water-tight seals are specifically engineered to prevent rainwater from entering the truck bed. The overlapping design of the panels ensures that rain is channeled away from the bed, keeping your cargo dry.

But as I mentioned earlier, it may or may not leak. Also, do not entertain the thought that tonneau covers are completely waterproof. None of them are waterproof they are made water-resistant with the help of seals.

Now, you must be wondering do all tonneau covers leak? Or just the hardcovers? Read our detailed article to find out https://toptonneaureview.com/do-all-tonneau-covers-leak/


The UnderCover Flex’s panels are constructed from aluminum coated with a Fiberglass Reinforced Polymer (FRP) which can withstand the impact of hail better than some other materials, though in severe storms, like any vehicle component, it can sustain damage.

Snow and Sleet

The cover’s sturdy build helps it to support the weight of snow and sleet without bending. The FRP material also doesn’t get brittle in cold weather, which is good.

Sand and Dust

When it comes to sandy and dusty environments, the UnderCover Flex’s seals come into play again, keeping the fine particles out of the truck bed. The textured surface of the cover is also less likely to show scratches from sand or dust.

In summary, the UnderCover Flex is equipped to handle a range of weather conditions, keeping your cargo protected against the elements. However, like any product, extreme conditions will test the limits of materials and design.

Is UnderCover Flex secure?

The UnderCover Flex offers a solid level of security that’s on par with what you’d expect from a hard tonneau cover. Its robust aluminum panels provide a strong barrier that’s not easily penetrated, adding a tough layer of protection over your cargo.

The design ensures that the cover can’t be opened without first unlocking the tailgate, integrating nicely with your truck’s built-in security features.

However, it’s important to stay realistic about security. While the UnderCover Flex is secure, no lock is entirely unbreakable, and a determined thief with the right tools and enough time can get into almost anything.

That’s why it’s also crucial to consider what you’re storing in your truck bed and where you’re parking. If you’re leaving valuable items in your truck, especially for extended periods or in less secure areas, you’re going to want to be more cautious. And that applies to all the tonneau covers in the market.

In essence, the UnderCover Flex provides a strong deterrent to casual thieves looking for an easy target, but as with any vehicle, mindful parking and awareness of your cargo are your best defense against theft.

Is UnderCover Flex Worth the Money?

UnderCover Flex at $1,099 offers a good amount of durability and security. It is neither expensive nor cheap it lies in the middle while providing great build quality.

With a 3-year warranty and a 30-day money-back guarantee, you can trust in its quality and have a safety net if it doesn’t meet your expectations.

If you’re after a hardcover that’s easy to use and holds up against the elements, it’s definitely worth considering. It’s not just about spending money on a cover but investing in the protection and functionality of your truck bed.

Take Home Notes

In wrapping things up, the UnderCover Flex tonneau cover is a good hardcover. It’s not super cheap or overly pricey, but it feels fine. It makes your truck more useful and looks good while doing it.

If you want a cover that’s solid, looks cool, and is easy to use, the UnderCover Flex is a really good choice. It’s all about getting good quality that feels like you’re getting your money’s worth.