Vehicle 2021 Ford F-150

UnderCover FX21021 Flex Hard Folding Tonneau Cover Ford F-250/F-350 17-25 6'9"

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Item:
  • FX21021
Brand UnderCover
T-Slot Rails No
Material Type Hard
Box Weight 68 lbs
Box Length 81 in
Box Width 32 in
Box Height 8 in
UPCCode 816391020417
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$1,049.99
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2021 Ford F-150
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View parts that fit your vehicle Hard Folding Covers

For ultimate cargo protection, you can’t beat a rugged, hard tri-fold bed cover, like the UnderCover® Flex from RealTruck®. The premium truck bed cover offers a robust and secure hard-shell construction, easy-to-use folding design, low-profile aesthetic, and exceptional weather resistance, protecting your truck bed in all conditions.

The UnderCover Flex Tonneau Cover features rigid yet lightweight aluminum panel construction for superior durability. These panels are impact, abrasion, and cut-resistant—they can even support up to 400 pounds when evenly distributed. UnderCover treats the Flex Tonneau Cover with a durable gloss-black coating for superior corrosion resistance and sleek styling.

Accessing your truck’s cargo area is simple and quick—simply drop the tailgate, pull either of the cover’s release cables, and fold the cover onto itself toward the bulkhead. You can secure the cover in the ⅔ open position with the integrated safety straps or fold it flush against the rear window, securing it with built-in prop rods for 100-percent bed access. When you’re finished loading or unloading, close the tonneau cover, fasten and lock the tailgate, and your cargo in the bed is safer than your cargo in the cab. Installing the UnderCover Flex is just as easy using UnderCover’s clamp-on mounting system.

The UnderCover Flex is just as resistant to inclement weather as it is to theft. The tonneau cover’s EPDM rubber hinges, perimeter seals, and dual-action tailgate seal prevent moisture from seeping into the bed. Any water that slips past the side seals gets diverted through built-in water channels and out of integrated drain tubes, keeping your cargo dry.

  • Premium hard-folding tonneau cover
  • Easy-to-use tri-fold design
  • Durable yet lightweight aluminum-skinned panels
  • Corrosion-resistant gloss-black textured finish
  • Flush, low-profile design
  • EPDM rubber hinges, perimeter seals, and dual-action tailgate seal
  • Integrated drain channels and tubes
  • Offers complete full bed access when folded flush against the cab
  • Simple no-drill installation
  • 400-lb. weight rating (evenly distributed)
  • Limited 3-year warranty

Brand UnderCover
Material Aluminum
T-Slot Rails No
Material Type Hard
Series Flex
Submodel 6'9" Bed
Type Cover Hard Folding
Color Gloss Black
Fitment 2017 Ford F-250, 2018 Ford F-250, 2019 Ford F-250, 2020 Ford F-250, 2017 Ford F-350, 2018 Ford F-350, 2019 Ford F-350, 2020 Ford F-350, 2021 Ford F-250, 2021 Ford F-350, 2022 Ford F-250, 2022 Ford F-350, 2023 Ford F-250, 2023 Ford F-350, 2024 Ford F-250, 2024 Ford F-350, 2025 Ford F-250, 2025 Ford F-350
Box Weight 68 lbs
Box Length 81 in
Box Width 32 in
Box Height 8 in
UPCCode 816391020417
UnderCover FX21021 Flex Hard Folding Tonneau Cover Ford F-250/F-350 17-25 6'9"
Brand UnderCover
Material Aluminum
T-Slot Rails No
Material Type Hard
Series Flex
Submodel 6'9" Bed
Type Cover Hard Folding
Color Gloss Black
Fitment 2017 Ford F-250, 2018 Ford F-250, 2019 Ford F-250, 2020 Ford F-250, 2017 Ford F-350, 2018 Ford F-350, 2019 Ford F-350, 2020 Ford F-350, 2021 Ford F-250, 2021 Ford F-350, 2022 Ford F-250, 2022 Ford F-350, 2023 Ford F-250, 2023 Ford F-350, 2024 Ford F-250, 2024 Ford F-350, 2025 Ford F-250, 2025 Ford F-350
Box Weight 68 lbs
Box Length 81 in
Box Width 32 in
Box Height 8 in
UPCCode 816391020417

Warranty Information

1. UnderCover Ultra Flex

Warranty: Lifetime on the frame, 5 years on components.
Conditions: Applies only to the original owner with purchase from an authorized dealer. Not valid for transfer or reinstalling on another vehicle.
Limitations: Does not cover improper installation, accidents, misuse, or chemical damage.
Repair/Replacement: Upon evidence of defect, the manufacturer will decide on repair or replacement.

2. UnderCover SE

Warranty: Lifetime on the body, 1 year on hardware and lift mechanisms.
Conditions: Valid only for the first purchaser with proof of purchase and standard installation.
Limitations: No coverage for misuse, modifications, or negligence.
Repair: Through authorized service only. Transportation costs are not covered.

3. UnderCover LUX

Warranty: Lifetime on structure and factory paint.
Conditions: Only for the first owner and initial installation.
Limitations: Invalid if painted outside the factory, improper use, aggressive cleaners, or environmental damage.
Care: Clean regularly with automotive-safe products.
Repair: Decision made after condition assessment.

4. UnderCover Flex

Warranty: Lifetime on core structure, 5 years on other parts.
Conditions: Covers only original purchaser through authorized dealers.
Limitations: Not warranted against damage from misuse or external elements.
Repair: Performed through official service channels if needed.

5. UnderCover Elite

Warranty: Lifetime on ABS body, 1 year on lift parts and hardware.
Conditions: Valid for original owner with receipt.
Limitations: Excludes improper installation, driving with lid open, unauthorized modifications, or environmental/chemical damage.
Repair: Through official channels; shipping at owner's cost.
Note: Remove cover when transporting oversized items.

6. UnderCover Elite LX

Warranty: Lifetime on structure and factory paint, 1 year on hardware.
Conditions: Only valid for the original owner and first installation.
Limitations: Not covered if repainted, used open, or exposed to aggressive substances.
Care: Use only safe products for plastic and paint.
Repair: Manufacturer decides based on defect evidence.

7. UnderCover SwingCase

Warranty: 1 year on the entire product, including body, locks, hinges, and hardware.
Conditions: Valid from purchase date for original buyer with receipt.
Limitations: No coverage for installation errors, negligence, chemical or mechanical damage.
Care: Clean only with plastic-safe products.
Repair: Repair or replacement available via seller upon manufacturer approval.

How to Submit a Warranty Claim

If a defect is discovered during the warranty period, the product may be returned to the place of purchase, subject to prior approval. Unauthorized returns will not be accepted.

Provide the following:
  • Order number
  • Full name, address, phone number, email
  • Vehicle year, make, and model
  • Product name or part number
  • Description of the issue
  • Copy of original receipt
  • Photos showing the defect

All claims will be reviewed only upon submission of a complete data package and proof of defect.

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