Unihertz Atom Smartphone Review - The World’s Smallest Rugged Smartphone

The Atom is full-sized Android in the tiniest ruggedized package.

Unihertz has followed up on its previous micro-smartphone, the Jelly, with a rugged masterpiece in minuscule engineering called the Atom, offering a full Android experience in the smallest durability-focused form factor ever devised. Of course, that means that there is a laundry list of trade-offs and only a relatively small niche audience who the Atom might appeal to in the long-term. Throughout our time with this handset, the novelty of that didn’t really wear off and using the phone was plenty of fun thanks to well-optimized inputs and generally great performance -- for what this is. But problems did arise in terms of day-to-day use, admittedly mostly because some text is difficult to read without brilliant eyesight. Furthermore, audio quality isn’t awesome and the camera suffers some issues. That does not, however, mean that this device is any less worthy of consideration. For a number of users and lifestyles, in fact, the Unihertz Atom will be a perfect fit precisely because of its small size and durability.


In terms of specs, the mid-range Unihertz Atom measures in at just 96 x 45 x 18 mm and tips the scales at just 108g. At that scale, the forward-facing fingerprint scanner takes up around a third of the total width and the camera housing at the back takes up around half. The primary shooter is a 16-megapixel sensor with autofocus while the selfie camera is a fixed-focus 8-megapixel snapper. The display panel measures 2.45-inches with a resolution of 240*432 pixels, presenting users with a much-minimized full version of Android 8.1 Oreo. Pixel density falls in at around 203 PPI, giving a surprisingly clear image quality for the Atoms size. There’s no SD card storage expansion with the Atom but dual Nano SIM, in dual standby mode, can be accessed via the full-size SIM drawer. Storage is set at a healthy 64GB and a respectable 4GB of memory backs up the MediaTek P23 MT6763V/B octa-core SoC Unihertz included here. That’s four cores clocked at 1.51GHz and four further with a frequency of 2.0GHz for more demanding applications. A Mali-G71 GPU accompanies that processor.

The frame encompassing that, complete with headphone jack and USB Type-C port, is built of thick rubbery polycarbonates and plastics for added durability and only available in one color - Space Gray with red accents. That aids with the handset’s IP6G ruggedization rating. A programmable ‘PTT’ button is also built along the right-hand edge just below the power button and just opposite the volume buttons. A lanyard slot is built into the lower-back portion of the Atom for additional security against misplacing the tiny device. The Atom’s charging port is used both for powering up the 2000mAh battery and for OTG functionality while the headphone jack doubles as a receiver for FM radio. A single speaker can be found on the rear panel. Unihertz sets the price for this mid-range device at just $259.

In The Box

When the package containing our Unihertz Atom test unit arrived, it was small enough to be easily- confused for a smartwatch before closer inspection. In spite of its size, it does contain a fair number of inclusions beginning with the smartphone itself and a film-style screen protector. Buyers will find a USB Type-A to cornered USB Type-C cable under that as well as a wall adapter and a premium cloth tube lanyard. Finally, a user manual and a pamphlet outlining the 12-month warranty are included alongside a SIM tool. All but the lanyard are fairly standard inclusions to be packed in with a smartphone but this handset really doesn't require much by way of extras.

Hardware and Design

On the hardware front, Unihertz has done an exceptional job ensuring this smartphone will be durable. That’s due in large part to the size of this gadget. To begin with, it is noticeably thicker than other smartphones but not to such a degree that it’s difficult to hold. A fair amount of that heft is because the components have been squeezed into such a small frame but also because the outer protective coating is so thick. The panels, edges, and corners feature extra grip to make it more difficult to drop too. Meanwhile, the small screen size and use of an unspecified version of Gorilla Glass mean that there’s not enough surface area to really bend or twist. The entire build brings to mind the original candy-bar style Nokias from the 1990s and early-2000s. It really does just feel indestructible because of how compact everything is and might even pose as much a risk to bare feet as a Lego brick if the company had used harder materials and sharper edges.

In terms of design, as alluded to above, all of the edges and cornering is smooth and wide making the Unihertz Atom surprisingly easy to hold onto. What’s more, a lanyard slot is built right into the frame so that the device can be worn around one’s wrist or neck. The contours and material are grippy and give a good in-hand feel while the texturing on the red PTT button assist in finding the proper key to press under any given circumstance. For aesthetics, the Atom could be described as having an adorable -- albeit rugged -- charm. Only one color is available but the manufacturer made sure to include a red accent line that steps back from the garish oranges and yellows used on similarly hardcore handsets. All ports and jacks are open as well and that means that Unihertz went further still to ensure that waterproofing isn’t just enabled by difficult to manage rubber flaps. That makes plugging the device in, accessing SIM cards, or listening to music via headphones a much less daunting task without taking away from endurance.


The display is, as might be expected with consideration for its resolution, not exactly amazing. It’s actually not bad either although some pixels do obviously show through in more high-definition media. In fact, it’s pretty much a given that the purpose of this phone probably isn’t to watch movies or play games. That’s definitely possible but comes with serious drawbacks that might be better illustrated by explaining how navigating the more general UI is on a phone this size. Unihertz has not created a custom version of Android to run on the Atom and that means that everything is just scaled down. Reading the notification bar can, therefore, be a real hassle and will present problems for users without near perfect eyesight. It’s not unusable but it requires the gadget to be held up-close-and-personal where a normal-sized smartphone could be held almost at arm’s length. Fortunately, the company didn’t choose a low-quality panel either and even typing on the panel isn’t difficult. All touches and inputs register immediately with no latency.

Performance and Battery Life

Battery life from the Atom is about average thanks to its small screen and our benchmarks on that front lined up very well with real-world usage. That means that under constant use, it shouldn’t be difficult to get at least 5 to 6 hours of screen-on time between charges. Charging itself takes around 1.5 hours to accomplish. Now, it’s worth noting that our benchmark and use was under sub-optimal conditions since we left the screen brightness turned all the way up and all power-saving turned off. The benchmark also kept the internal hardware pegged at over 70-percent capacity for nearly the entire test. So anybody should be able to squeeze more out of this handset just by adjusting the settings. On standby, the Unihertz Atom lasted us between 2 to 4 days with intermittent use.. The benchmark for performance, on the other hand, was much less impressive but not surprising. The single-core score fell in at just 779 and the multi-core score at just 3687 via GeekBench's measurements. That score wouldn't be expected to allow the latest and greatest smartphone games or most intensive apps to run smoothly at all.


Benchmarks do not always fairly represent any given piece of hardware though and that is certainly the case here. Although the display size is such that it really makes almost no sense to download anything with lots of on-screen controls, we were able to run through a dozen or so races on Asphalt 9: Legends with no signs of lag in sight. The main driving method in that game is fairly hands-off, making for a great experience -- setting aside the very low screen resolution and the need for the smartphone to be held as near the face as comfortably possible. Other apps such as Helix Jump were not quite so much fun due to the need to swipe across the screen, blocking almost the entire view and making accurate play impossible. To the contrary, using intensive photo editing apps like Prisma or Pixlr was equally smooth and similarly only hampered by the scale of the viewing real estate. So using this smartphone just like any other isn’t completely out of the question under the majority of circumstances for those who won’t be bothered by the tiny display.

Connectivity and Audio

Audio with the Atom is very poor. That’s not to say it isn’t loud but, aside from eyesight related problems users might have with this smartphone, it is not high-quality in any sense of the word. Bass is nearly non-existent and high-tones are tinny. This is not an Android device for audiophiles. Audio quality over headphones or Bluetooth is as good as can be expected but there’s no specialty hardware there either. So the Atom shouldn’t be expected to produce the high-fidelity noise of modern flagships or even some mid-range devices.

For connectivity, the Unihertz Atom features all modern features that should be in any Android handset. NFC is available for tap-to-pay. Both Bluetooth 4.2 A-GPS and GLONASS ensure that some level of connectivity can be had outside of dual-band Wi-Fi or Wi-Fi hotspot features. Mobile data is fairly robust, as outlined below, and will work with either AT&T or T-Mobile in the US. We were connected over T-Mobile through our MVNO and saw no issues with the 4G network in our area. No latency or problems were present in any of the other technologies either and a phone call showed that the earpiece volume and quality in the Atom were well above serviceable. This particular smartphone is designed to be, for lack of a better term, a phone first and foremost.

GSM: Bands 2, 3, 5, 8

WCDMA: Bands 1, 2, 4, 5, 8

TD-SCDMA: Bands 34, 39

FDD LTE: Bands 1, 2, 3, 4, 5, 7, 8, 12, 13, 17, 18, 19, 20, 25, 26, 28A, 28B

TDD LTE: Bands 34, 38, 39, 40, 41

CDMA2000: Bands BC0, BC1


The software environment on the Unihertz Atom is as one might expect from a near stock installation of Android 8.1 Oreo. Aside from an additional settings menu item, called ‘Smart Assistant’, everything is as it should be on the firmware side of things. Under that menu, Unihertz has included a physical key switch toggle, an option to gradually increase volume on incoming calls, LED controls, flip to mute options, and battery saving features. That’s also where the controls for the reprogrammable red ‘PTT’ physical button are found. That can be set to launch any application while the power button can still, like almost any Android 8.1 Oreo smartphone, be used to launch the camera. The software experience itself is very smooth regardless of the relatively low-powered internals. That’s likely down to the fact that the internal components aren’t working quite so hard because of the phone’s size in terms of display output. During our test, the handset received one update that squashed some bugs with Bluetooth and other features. However, it is worth noting that the security patch on the Atom is still on 'May 5 2018', for now.

The entire OS is present as well as all of the expected UI but scaled way down to the point where things can be a bit difficult to read if the font size is set too small. It will be a challenge for older users or those who may be visually impaired to use this handset. Thankfully, Android’s easy-to-read icons help out with the navigation side of things. The virtual keyboard is actually surprisingly easy to type with despite that a single finger can easily cover more than three of the digital keys. That's without even using swipe inputs. Although that option would likely improve things further, typing was accurate enough that we didn't feel the need to ever turn that on. That's not to say it's at all perfect. We did manage to bungle putting in a password or three upon first use but several log-ins later errors stopped happening with any noticeable frequency. All of the expected Google software and stock tools such as a clock and file manager are present.

In terms of extras, Unihertz also includes a Cell Broadcast app for checking emergency alerts in the user’s immediate vicinity and an SOS app for setting emergency contacts and quickly sending out emergency calls, messages, or ‘SOS’ including location data. Similarly, a TrackBack application is installed out-of-the-box that enables accurate tracking of where a user has traveled and how far. That would be useful in emergency situations as well as tracking distance for comparison with the included pedometer app. Zello is included for walkie-talkie functions as well as an FM radio and the former of those is initially linked to the above-mentioned PTT button. Last but not least the Atom includes a ‘Toolbox’ that contains various useful DIY and measurement apps. Of course, a flashlight, compass, alarm, and camera-based magnifier are part of that package. But there's also a sound measurement app to gauge the level of noise in a given environment, a bubble level, a height measurement tool, a picture hanging level, a digital plumb bob, and a protractor. Finally, the camera can be used as a heart monitor in a pinch and the app for that is included in the Toolbox.


The primary camera included in the Unihertz Atom is a mixed bag. On the one hand, well-lit shots can turn out very well and color capture is unbelievably accurate but it also has quite a few shortcomings. Not least amongst those is the fact that even relatively tame and diffuse light coming from behind the subject will wash out the resulting picture with a high-level of consistency. Meanwhile, indoor shots are a challenge to take due to the size of the phone. Not only do the sensors begin to lose detail as light dwindles but the sensor struggles to capture images in those conditions because of how difficult it can be to hold the Atom itself still. We saw quite a bit of blur in indoor shots despite taking those multiple times. Of course, a photographer with a more stable hand or smaller hands might not have those issues and there are plenty of features as there would be on larger devices -- such as HDR mode, filters, and other finer controls. Not every user’s experience with this camera will be the same but it was a low point from this device for us. The face-unlock feature, contrarily, worked very well even in low-lit circumstances. That's not to say it is the most secure since it only utilizes a single camera sensor, making it impossible for more advanced face recognition features to be implemented.

The Good

Small form factor means the Atom goes anywhere without getting in the way

IP68 dust, water, shock, temperature, and vibration ruggedization

Relatively easy to use in spite of its size

Dual SIM standby with plenty of bands supported

Useful DIY features and a programmable button for quick app access

Android 8.1 Oreo

Storage, SoC, and RAM are relatively high value for the cost

3.5mm headphone jack

The Bad

Apps that require a lot of physical interaction can become unusable

Reading the display is going to be difficult for a significant number of users

The camera is difficult to use due to size

The camera doesn't handle unsteady shots well at all

The camera doesn't handle backlighting or low-light circumstances very well

Audio is abysmal but loud and good enough for ringtones, alarms, or alerts


There is a lot about the Unihertz Atom that really bolsters its appeal, as outlined above. In particular, it would be a great handset for those who don’t necessarily need a smartphone taking up room in their pocket or for those who don’t want their device to become a distraction. Android phones are already very portable but the Atom also excels on that front. It can quite literally be placed in a pocket and forgotten about until its needed and that's not a bad thing at all. On the other hand, it will do just about anything a full-sized smartphone will when it needs to. The audio quality isn't great, the camera's not perfect, and the screen is far too tiny to be any use for those with larger hands or poor eyesight but those aren't really the focus here. Instead, the Atom aims to be durable and functional without getting in the way and that's precisely what it does.

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About the Author

Daniel Golightly

Senior Staff Writer
Daniel has been writing for AndroidHeadlines since 2016. As a Senior Staff Writer for the site, Daniel specializes in reviewing a diverse range of technology products and covering topics related to Chrome OS and Chromebooks. Daniel holds a Bachelor’s Degree in Software Engineering and has a background in Writing and Graphics Design that drives his passion for Android, Google products, the science behind the technology, and the direction it's heading. Contact him at [email protected]
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