Two for the price of one. Two birds with one stone. Two heads are better than one. It’s a fairly simple concept: if having one of something is good, then having two of that thing is even better.

The Axon M has a trick up its sleeve

At face value, ZTE’s Axon M doesn’t look like a $725 smartphone. The design is chunky for a modern phone, although the squarish aluminum chassis is comfortably weighty to hold. Turn on the device, and you’re greeted by a 5.2-inch, 1080p panel with bezels that feel massive compared to more modern devices like the Essential Phone, Galaxy S8, and iPhone X. The rest of the specs are just okay, with last year’s Qualcomm Snapdragon 821 processor and 4GB of RAM. Even the software is a year old: it runs Android Nougat, instead of Oreo (although ZTE is promising an update further down the line).

But the Axon M has a trick up its sleeve, something that no other phone is equipped with. More accurately, this trick is hidden behind its back: a second screen, that flips out to create a mini tablet of sorts. So, let's talk about those screens.

Like the “main” screen, the second Axon M screen is an identical 5.2-inch, 1080p display, which results in a larger 6.75-inch combined screen when unfolded. There are three different modes ZTE offers for taking advantage of the second display, which can be switched between through an extra “M” button that the company adds next to Android’s usual software buttons for going back, home, and multitasking.

Dual mode is probably the most useful option

First up is the simplest mode, called “dual mode.” As the name may suggest, dual mode lets you run two apps side by side, one on each screen. It works in both portrait and landscape modes, and it’s probably the most useful and most functional of the three modes. Being able to run Google Maps side by side with an email so I could get directions while looking up what floor I was supposed to go to was actually kind of useful, or even just the ability to message a friend while not leaving the YouTube video I was watching all works well. In dual-screen mode, each app gets its own set of software hot keys, letting you close out one and open up a new one without disturbing the other. The Axon M also manages audio, so that you’ll only hear the screen you’re actively interacting with if both are trying to play. And while the specs aren’t the latest and greatest, the Axon M still holds up well, even for more demanding tasks like watching Netflix and playing a game at the same time.

Next is “extended mode,” which lets you run a single app on both screens in a tablet-like experience. Out of the box, ZTE has worked to optimize some of the more popular apps in the Play Store, including Facebook, Chrome, YouTube, and Twitter, but if your app hasn’t been optimized for the Axon M, you’ll need to force it to manually run in full-screen in settings through a universal toggle. Generally, everything I tried worked mostly well, even apps that weren’t specifically optimized for the larger screen, but your mileage may vary depending on what app you’re using.

ZTE has worked to optimize some of the more popular apps, but your mileage may vary

More disappointing is that oftentimes I couldn’t really find a reason to actually use extended mode. Video — which would seem to be the best use for the larger screen — tends to gain the least from the second display. It gives you a marginally larger picture at the expense of large black bars on the top and bottom, and a bezel divides the screen in the middle; 4:3 fullscreen formatted content fares much better, but I can’t recommend buying a $725 smartphone to watch Cheers or Fraiser reruns on Netflix.

It’s also strange how much ZTE pushes video on the Axon M, too. There’s even a dedicated hardware button that can be mapped to instantly launch video apps like YouTube, Netflix, or DirecTV with a single press. (But it’s not really the best way to take advantage of the two-screen concept.)

It still feels like there’s more that could be done with the two-screen concept

Apps like Chrome, Facebook, and Twitter take better advantage of the screen real estate, but those run into the same problem that Android tablets have always had: they just don’t optimize that well for larger tablet-sized displays. The other weird quirk is that, due to how Android measures the screen sizes, holding the device vertically (with the two screens side by side) will get you the “tablet” version of an app, albeit one that feels too short; rotating the display produces a taller version of the standard smartphone version.

For now, it still feels like ZTE is only giving the most basic options for what you could do with two screens. There are occasional glimmers of potential, like running YouTube in full-screen on one display while being able to browse or find a new video to watch next undisturbed on the bottom, but it still feels like there’s more that could be done. Why isn’t there an e-reader app, for example, that lets me put two pages of a book on the two screens, like, say, an actual book? Or a gaming function that offloads the virtual buttons on one screen with a digital controller?

Lastly, there’s “mirror mode,” which simply mirrors content onto both screens. ZTE envisions people using this to fold the phone into a tent-like position and watch videos together. I can’t say this was a use case that ever came up outside of just testing to see if it works, but it’s there if that’s something you want to do.

There are also software gestures that, in theory, allow you to quickly swipe to switch between modes, sending an app from one screen to another or extending it across both displays with quick gestures, but unfortunately they’re pretty hit-or-miss to use in practice. I spent a lot of time swiping futilely at the bottom of the display, before giving up entirely to just use the manual button.

I spent a few days using the Axon M as my main phone, and even with pretty heavy use of the two screens, the 3,180mAh battery didn’t have any problems making it to the end of the day with at least a 15 percent charge left. But while the screens don’t hurt battery life that dramatically, there are definitely parts of the ZTE Axon M that feel like the price you pay for having the second display.

There are parts of the ZTE Axon M that feel like the price you pay for the second display

For example, there’s only a single 20-megapixel camera on the Axon M. Hitting a button to switch between the front- and rear-facing camera on this phone actually flips the entire screen around to the other display. It’s a clever solution, but it’s awkward to use in practice, and would leave me in weird situations where I’d exit out of the camera app after taking a picture with the “rear” sensor, only to be faced with a black screen because the phone was now backwards. (The camera is mounted above the left, or primary display.) This also means that apps that use the camera (like Snapchat) work extremely poorly in the dual-screen modes, since they can only take awkwardly positioned selfies.

The placement of the hinge on the right side of the Axon M means that all the buttons are shifted to the left, including the power button, which flies in the face of years of ingrained logic from iPhones, Samsung Galaxy phones, Google Pixels, and almost every other major phone. On more than one occasion, I picked up the phone and thumbed the power button only to realize that I was holding it upside down, and that the “main” screen was on the other side.

A final weird hardware quirk was that the two panels on our review device seemed to be calibrated differently: one displayed warmer colors, and one was slightly cooler. It’s not a deal-breaker, but it was something noticeable, especially when running some apps extended across the two displays.

The Axon M isn’t the first attempt at a dual-screen Android phone. The benefit of time and more powerful hardware means that the Axon M can actually follow through on some of the promises, like running multiple apps and full-screen integration, that precursors like the Kyocera Echo simply weren’t able to do.

It’s probably worth sticking to one screen for now

But if the Axon M is the first dual-screen phone that can actually execute the idea of a two-screened device, using it in practice has me doubting whether the idea actually has practical merit. It is cool, on a purely technical level, to be able to unfold your phone and run a giant version of Alto’s Adventure or two apps side by side. But between the hacked-together software execution and the overall lack of productive application for it, it’s hard to look at the Axon M as anything more than a fun gimmick. And with the hefty $725 price tag and a plethora of more powerful, better-designed, and cheaper Android flagships out there, it’s probably worth sticking to one screen for now.