Undercover Hard Flex Folding Truck Bed Tonneau Cover Review

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Undercover Hard Flex Folding Truck Bed Tonneau Cover Review

Running a truck with a flatbed is great for transporting heavy loads, work equipment, tools, and a multitude of other things. There are times when you need to keep the contents covered because of the weather or because there may be something of value in there.

Soft covers are available but don’t always cut them, They are easily cut open and the contents can be easily stolen.

Choosing a hard folding truck bed cover keeps all of the elements out and your belongings secure inside.

UnderCover is a well-established American brand that makes a variety of hardcovers, we have taken a look at each one and found their positive and negative points.

Read our UnderCover Hard Flex Folding Truck Bed Tonneau Cover Reviews to help you make the most informed buying decision.

5 Best Undercover Hard Flex Folding Truck Bed Tonneau Cover

Last update on 2022-12-01 at 05:31 / Affiliate links / Images from Amazon Product Advertising API

1. Undercover Flex Hard Folding Truck Bed Tonneau Cover | FX21019

The first thing that you need to know is that this hardcover is an easy fit, no drilling is required. Secondly, it doesn’t need a key to lock securely, as long as the tailgate is locked, no one can open the cover.

Each panel is made from FRP, a metal that is lighter, stronger, and more scratch-resistant than aluminum.

It has a gloss black finish which looks impressive on any truck, and it has an incredibly low profile, it fits flush with the truck.

Best feature

Operating the folding panels is easy, there are automatic latches and pull cords that can be worked from either side of the truck. You can drive with the cover closed, open, or locked in a semi-open position. The tough rods hold it in position and don’t allow it to knock against the rear of the cab.

The rubber seals that run around the entire cover ensure barely any moisture can get through. There are drainage tubes that pour any rain away from the truck.


  • 3-year hassle-free warranty
  • Made in the USA
  • The cover allows 100% bed access
  • Easy to install, lightweight cover
  • Weatherproof
  • Hard and durable
  • 3-positions even while driving
  • Secures contents of the truck


  • Install is much easier with 2-people
  • Seals may weaken over time and need re-gluing
  • No interior light

2. Undercover Ultra Flex Hard Folding Truck Bed Tonneau Cover | UX22019

This is the next step up hard bed tonneau cover from the UnderCover range. This does everything that the Flex cover does, and more. Instead of a high-gloss finish, the Ultra-Flex is matte black.

The rear of the cover, near to the tailgate, has an LED strip light that illuminates brightly. This is great for pack or unloading the truck in darkness.

Best feature

The Ultra-Flex is constructed of 3-foldable panels that are lightweight yet exceptionally durable. Each panel has a soft carpet lining on the underside. This ensures that valuable or breakable contents are protected.

The folding tonneau cover doesn’t restrict any access to the truck’s bed. When in the fully-open position there is 100% of the storage space available.

If your load is particularly large the truck can be driven with the cover open as there are 2-rods that hold it securely in place.

The specially designed dual-action tailgate seal enables it to be closed regardless of the cover being open or shut, this saves time when compared with other brands of truck bed covers.

The seal that goes around the entire cover provides maximum leakage protection, keeping the contents dry.


  • 5-year hassle=free warranty
  • Made in the USA
  • Carpeted under-paneling
  •  LED  strip light
  • Exceptionally durable
  • Sealed for water-protection
  • 3-position cover, drivable in each position
  • Installation requires no specialist tools
  • Easy open/close latches from either side


  • some users found that the side rails could be a fraction longer
  • Installation requires some manipulation to get it perfectly aligned

3. Undercover Flex Hard Folding Truck Bed Tonneau Cover | FX21002

This short-bed folding cover is easy to install and operate. Each of the 3-panels is made from very light and exceptionally durable aluminum, as are the automatic latches. They lock into place easily and can be quickly released from either side of the truck, via pull-cords.

Just as the other UnderCover tonneau featured in our review do, this one also can be positioned in 3-ways; closed, open, and semi-open. It is safe to drive whilst in any of these positions as the strong prop rods hold everything in place.

Best feature

Installation is a 1-person job, though we think with 2-people it is even quicker and easier. Once it is installed, the gloss black cover will sit flush with the truck. It enhances the look of a vehicle without hindering or obscuring rear-vision.

Due to the tough aluminum construction, the cover is expected to last for many years. It won’t rust and the rubberized seals that run around all of its edges keep virtually all rainwater out.


  • 3-year, hassle-free warranty
  • Made in the USA
  • Multi-positions
  • Provides 100% truck bed access
  • Automatic latches enable quick, smooth operation
  • Full tailgate use without needing to lift the cover
  • Strap and buckle system holds everything in place
  • Weatherproof seal around the entire perimeter


  • Not carpeted on the underside
  • No inbuilt light
  • Components could have been powder-coated to prevent paint chips

4. Undercover Ultra Flex Hard Folding Tru​​ck Bed Tonneau Cover | UX12019

This is an UltraFlex tonneau cover that has a stylish matte black finish. Installation is simple and the tight, durable fit ensures that no water can pool ensuring the inside of your truck remains dry. Heavy snowfall doesn’t bother it either; it can withstand a coverage of up to 400lbs.

As with the previous covers featured in our folding truck bed cover reviews, this too has the multi-positional feature, open, closed, partially open, all of which can be in operation as the truck drives.

We love that the cover can be locked into an upright position using 2-rods. It doesn’t lean against the cab at all yet folds back right up to it to give you maximum access.

Best feature

As with all of the UltraFlex covers, the underside is carpeted. Not only does this muffle any noise but it also adds a cushioned protection to the cargo that you’re carrying.

Don’t forget the LED light strip that illuminates the entire space that makes packing and unloading the truck an easier job.

It is lightweight which means opening and closing it can be done in a matter of seconds. All of the latches are made from aluminum which ensures their strength for years to come.

Removing the cover also takes seconds, it only requires loosening 2-knobs.

This is a superb piece of kit that will secure all of your belongings and help them to stay dry.


  • 5-year hassle-free warranty
  • Made in the USA
  • Secures utilizing the tailgate lock
  • Carpet-lined panels
  • Multi-positional, even while driving
  • Perimeter systems and drainage tubes
  • Includes LED light strip
  • Dent-resistant, weather-proof, and durable
  • Enhances the look of the truck


  • Instructions could be clearer, some users rely on online videos
  • Routing of drainage tubes is awkward

5. Undercover ArmorFlex Hard Folding Truck Bed Tonneau Cover | AX42008​​

Some brands of truck bed covers require you to lift the cover before you can gain entry to the rear of the truck, not so with any of the range of UnderCover products. Simply lock the tailgate and walk away knowing that your contents are secure. Unlock it again and throw your luggage or shopping straight beneath the cover.

The ArmorFlex cover can do everything that the Flex tonneau cover does, but as the name suggests, it is virtually impenetrable.

Best feature

The patented LINE-X coating gives the cover superior strength and durability. If you live in harsh weather conditions or push your truck to great extremes, you should consider this cover. The coating adds further protection to the cover and makes it resistant to dings, dents, and scratches. Rest at ease knowing that the stones that flick up from the track won’t damage your hardcover.

The aluminum panels can withstand heavyweights, so resting a large toolbox as you unload your truck won’t cause it any both.

The cover won’t compromise the storage space either, 100% of the space is still available as the cover sits perfectly flush to the top rails.

Opening and closing take seconds and the quality construction means it operates smoothly.

This is a beautiful hardcover that not only makes any truck look brilliant, but it will also seal out any rain and keep the thieves away.


  • 5-year, hassle-free warranty
  • Made in the USA
  • LINE-X coating provides an added, ultra-tough, protection
  • Suitable for extreme terrains and climates
  • Matte black finish with flush fit enhances any truck
  • Auto latch and lock system
  • Multi-positional, even whilst driving
  • Aluminum framework for durability
  • 100% access to the truck bed


  • Most expensive in the range
  • Not carpeted on the underside

Features and Factors of UnderCover Truck Bed Covers

Traditionally, hard tonneau covers for truck beds have been made from fiberglass. UnderCover has created FRP that is even tougher and more durable.

Here are a few more of the reasons why you should choose UnderCover.

Foldability. Each cover features a multi-position folding action allowing the user to carry larger loads without the need to remove the cover.

Simple 1-tool installation. The truck bed cover takes advantage of the truck’s existing body kit and only requires a wrench for tightening.

Aerodynamic. The sleek, flush design enables air to flow right across it and can improve miles per gallon by up to 10%

Strength. FRP offers unrivaled toughness and durability whilst remaining lightweight enough for smooth ad fast operation.

100% access. The cover positions allow access to every part of the truck bed.

Security. Utilizing the locked tailgate, contents can be stored safely and prevent theft.

Weatherproof. Keeping out 100% of rainwater is a virtual impossibility, all brands know that. Undercover comes as close as possible to being totally leak-proof.

Are UnderCover Flex Folding Truck Bed Covers Leak-proof?

Each style of the tonneau covers is advertised as ‘weather-proof‘ or ‘water-resistant‘. It is a virtual impossibility to keep 100% of rain out of an open-backed truck with an after-market product.

With that said, many users have ventured through car-washes successfully and barely noted a drop of moisture.

Each model featured in our truck bed hardcover reviews has a perimeter seal and drainage tubes, the vast majority of rainwater will just runoff.

What we do recommend is paying particular attention to the placement of the drainage tubes nearest to the tailgate; this could ensure no rain sneaks in.

Of all of the brands that we have researched, we found the UnderCover Flex truck bed tonneau covers range to be the most weather resistant.


What is a tonneau?

This is the area of a truck or car that is open from the top and can carry cargo or people. In the case of a truck, it is the bed at the rear of the vehicle.

Do you need specialist tools to fit an Undercover Flex folding truck bed cover?

Not at all, in fact, you will only need a 1/2″ wrench. The cover utilizes the truck’s rails therefore no drilling is required.

Can you remove a tonneau cover quickly?

Absolutely. If you’re selling your truck or have a rental and you need to remove the hard cover it takes a matter of seconds. There are 2-release knobs that you need to twist and then lift the cover straight off. It couldn’t be simpler.

What does FRP stand for?

Fiberglass Reinforced Polymers. This is the material that each Undercover Flex cover is made from. It is stronger, lighter, more dent-resistant, and weatherproof than aluminum.

What if my large load only needs half of the truck bed?

Each tonneau cover has a buckle and strap system that holds the cover in a position to keep unused space covered securely.


If you have spent a fortune on an amazing truck, it seems pointless to protect the contents with a flimsy covering or a soft vinyl one.

Now that you have read our UnderCover Flex Folding Truck Bed Tonneau Reviews, we hope to have helped you to choose the model that will keep your truck and its cargo, dry, safe, and secure.

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