BAKFlip MX4 and Undercover Ultra Flex are known as Low-profile Hard Folding Covers. Like the MX4 the Ultra Flex is made from aluminum making it lighter than polycarbonate or thermoplastic covers. This makes it easy to handle. It has one of the lowest profiles of any tonneau cover on the market giving it a sleek look while maintaining its strength.
BAK Industries BakFlip MX4
To open the truck cover you must pull the cable underneath the panel on either side, which activates the pull cable release mechanism. So you can lower the tailgate, pull the cable.
And then in a matter of seconds, you’re going to be able to access your full bed by just lifting up each panel and you don’t have to do it on that side. It can be on this side too. This cover flips up to give you full-bed access, which is very nice. When you need to haul up most of your bed, it can be propped up while you’re driving and you can go highway speed with this cover safely leaning against the back window.
The BAKFlip also offers a compatible storage box called a BackBox 2, which is a folding toolbox that clamps onto the side of the truck. The MX4 has rails that we clamp onto the side and a drain tube, which keeps the water out of the bed. If you undo this knob at the bottom, the whole cover can be removed in a matter of seconds, the rails will stay on. And these hooks just snap, lower the cover, strap it here and drive with it in place.
UnderCover Ultra Flex
Ultra Flex has a different finish. It’s more of a Satin Smooth Aluminum style. You’ll notice the Ultra Flex is easy to open, simply pull the cable on either side and lift up. A feature that’s really unique to it is its carpeted underside. Also, notice the lashes at each fold keeping the Ultra Flexes seal nice and tight and the profile low. To drive with the cover open simply secure the snap straps to hold it in place. The Ultra Flex can fully fold and stand on the end allowing for maximum use of the truck bed and it doesn’t lean against the truck’s rear glass. Many people like this feature.
Unlike the MX4 the Ultra Flex also comes with LED strip lighting. This makes loading and unloading gear a snap at night. You’re gaining truck luggage that goes on the side of the bed and you get these LED light strips that Mount to the side of the rail. So it’s a good little feature to have.
Unlike other tonneau covers, this cover has an integrated tailgate seal, which does not require you to shut the tailgate prior to shutting the cover. You can do either of them first. So pull the cable, fold it up. The Ultra Flex is also getting a little bit more bang for your buck.
Speaking of water the Ultra Flex has a channel underneath the seal that captures any water that makes it past the seal and drains it outside of the truck bed keeping the gear dry. You just flip the cover-up and then you come under and you undo this turning wheel and the whole cover pops off any water getting inside, goes out of the drain tubes in the back.
While a lot of other covers require drilling the Ultra Flexes channels simply clamp on to the bed rails. Removing the cover is even easier simply – turn the knob and the cover lifts right out of the bed. The closest competitor to the Ultra Flex is the BackFlip MX4.
We recommend the Ultra Flex because of its added-value, LED light strips, a carpeted underside, and the best warranty on the market – a five-year warranty. This tonneau cover isn’t a cheap knockoff disposable cover but it is a good value, it combines a sleek low-profile look with a multi-latch system, excellent water resistance, and ease of use.
So both the MX4 and the Ultra Flex are made by a company called Truck Hero. BAK Industries MX4 has a three-year warranty. UnderCover has a five-year warranty. So you’re getting a longer warranty with the Ultra Flex. Both of these are going to be good hard folding covers that give you full-bed access. It’s all a matter of preference if you like the lighter finish which matches the bed caps well or you want to go for that darker stealth look. Both of them are American-made and of high quality.