Onyx Boox Nova Air C review: Read e-book on Android, in color

Photos: Sandra Vogel/ZDNet

Onyx is a well-established maker of E Ink tablets that can accommodate pen input as well as run third-party apps, thanks to its Android app. Onyx devices come in different sizes for a range of use cases. I recently looked at a pair of e-readers/content creation devices – the 13.3-inch Boox Max Lumi2 and the 10.3-inch Boox Note Air2.

Onyx has now adopted the E Ink Kaleido Plus color display, which provides 4,096 colors on a low-power panel. This 7.8 inch Onyx Boox Nova Air C pairs with Android 11 and stylus-based inputs. It promises up to 4 weeks of battery life on standby and costs $419.99 / £399.99.


  • E-ink color screen
  • Android 11 and Google Play Store
  • collection pen
  • Good battery life

You do not like

  • Cover is optional extra
  • No MicroSD card slot for storage expansion

Apart from the color on its screen when the device is turned off, Nova Air C looks like many other e-readers. It measures 136.5mm wide, 194mm deep, 6.3mm thick and weighs 235g without its optional cap ($59.99 / £53.99). There is a Boox mark along the bottom edge, and enough side edge to hold the device securely without touching the screen. The design looks solid, and there are no rough edges in terms of quality.

There is only one button on the top edge that turns the device on and off. On the bottom edge are a pair of speakers and a USB-C port for charging. The edges lack any buttons or touch controls – you either tap the screen or use the actual page-flip buttons on the optional case to get around.

The Nova Air C is powered by the Snapdragon 662 chipset with 3 GB of RAM and 32 GB of internal storage. There is no MicroSD card slot to increase storage space, which is arguably a problem given this device’s ability to standardize all your e-books and audiobooks, as well as serving to some extent as a productivity tool thanks to its support for pen-based inputs.

For connectivity there’s Wi-Fi 5 (802.11ac) and Bluetooth 5.0, so the earbuds can be paired if the internal speakers are too intrusive for your location. I found the speakers to offer good sound quality for listening to material like podcasts. The USB-C port is used for charging, and can also be used to connect the Nova Air C to your computer, when it becomes available for drag-and-drop file transfer.

The Nova Air C’s 2,000mAh battery will last for four weeks in standby mode, according to Onyx. Since E Ink displays only consume power when updated, the power consumption is lower than regular tablets, phones or laptops. During testing, I regularly got a week of e-book reading between charges, although I was careful to turn off Wi-Fi when it wasn’t needed, to help conserve battery. There’s no fast charging here, so keep an eye on the power level and make sure there’s enough time to boost when it goes down.


Boox Nova Air C Cover Optional extra $59.99 or £53.99.

Photo: Onyx

It’s a pity that the cover for the device has to be purchased separately, at a rather high price of $59.99 / £53.99. Buy it and you’ll get a total spend of $479.98 / £453.98. I’m not a fan of the case’s silver coloring, but the magnets that hold it to the Nova Air C are strong. You can search the web for a suitable alternative protection if the budget is tight, and you will only miss a pair of actual page-flip buttons.

Fortunately, the stylus required to get the most out of the Nova Air C comes with the device itself. It attaches to the right side of the reader via magnets, and while the grip is fairly strong, it’s not secure enough to be a permanent solution. The case does not have a loop or slot to hold the stylus on, which meant that whenever I took the Nova Air C anywhere I was likely to need the stylus, I had to remember to carry it. In the long run, this will probably be a problem for me. A more reliable solution is needed, even if it means modifying the design of the pen or tablet to fit the housing on the device.

The 7.8-inch screen offers two different pixel densities thanks to the way the Kaleido Plus screen works. In color mode, the resolution is 468 x 624 pixels, giving a pixel density of 100 ppi, while in monochrome mode, this resolution goes up to 1,404 x 1,872 pixels and a pixel density of 300 ppi.

Onyx says the Kaleido Plus offers a 30% improved contrast in mono mode compared to its predecessor, as well as a 30% improved contrast in color mode and a 15% color improvement. These improvements come because touch response is now built within the screen itself rather than requiring a separate layer on top of the screen which, inevitably, forms a visual barrier to the screen itself. E Ink calls this “on-cell” capability.

Without the two devices side by side, these claims are hard to evaluate in real-world use, but my daily experience has been positive. I found reading the e-books quite satisfactory, and the page turned out to be as fast and clean as I would have expected from any e-reader. The screen size of 7.8 inches is also good – close to the ideal place for reading. I downloaded the Kindle and Kobo reader apps, as well as the Libby app that my public library uses. Everything works fine. There are plenty of fonts and sizes to choose from, and the device supports a range of document formats: PDF (Reflowable), PPT, EPUB, TXT, DJVU, HTML, RTF, FB2, DOC, MOBI, CHM. It also supports PNG, JPG, TIFF, BMP, WAV, MP3 and DRM audio via third-party apps.


Color – but not as you know it on a tablet with a backlit LCD or OLED screen.

Photos: Sandra Vogel/ZDNet

The color screen meant that I found myself enjoying magazines through my public library lending service like reading borrowed e-books. However, the E Ink Kaleido Plus screen is not as good at displaying colors as a normal tablet or phone. Don’t set your expectations that high.

Android 11 provides access to the e-reading apps you have installed, as well as to the rest of the Google Play Store. Besides, there are some pre-installed Onyx apps such as a dictionary, NeoBrowser web browser, Boox e-book store, and a note-taking app that allows you to create and save handwritten notes with the stylus. The pen has 4,096 levels of pressure sensitivity, and there are plenty of brushes, line widths and color options to work with.

Converting handwriting to text is supported, and I found this to be very accurate. You can also record the content of the spoken word – the microphone is on the bottom edge – and the resulting audio can be embedded in a document.

To help users work around the relative complexities of what’s on display, a small circle can be set to be always on the screen, and pressing this calls up nine shortcut buttons, which can be assigned to specific functions such as launching an app. However, the user interface is different from that of any other device, and there are so many possibilities and settings options, that it will take some time before exploring the full fury. This is not a criticism – it just highlights what a well-featured device this is.


The Onyx Boox Nova Air C is an interesting mix of an e-book reader, content creator, and tablet, with Android 11 offering a wide range of apps. It is well made, has a long battery life and comes with a built in stylus.

The lack of a MicroSD card slot to boost the 32GB internal storage is disappointing. E Ink’s color screen isn’t quite as vibrant as that of a regular tablet or phone, and screen updates are slow by comparison. The Nova Air C is by no means a replacement for either device, but the addition of a color display brings a welcome new dimension to the Onyx Boox lineup, which should please fans of its hybrid content consumption/creation approach.

Onyx Boox Nova Air C . specifications

an offer

E Ink Kaleido Plus, 7.8 inch, 4096 colors, touchscreen (Wacom + capacitive), 1872 x 1404 (300 dpi / 100 dpi in color), SNOW Field function

front light

moonlight 2


Qualcomm Snapdragon 662 Mobile Platform


3 GB


32 GB

My voice

Loudspeaker and microphone

wired connection

USB Type C

Supported file formats



Wi-Fi 5 (802.11ac)




2000 mAh Li-Polymer

Operating System

Android 11


136.5 mm x 194 mm x 6.3 mm




235 g

in the box

Onyx Boox Nova Air C, User Manual, Pen, USB Cable, Warranty Card


$419.99 / £399.99

Alternatives to consider

Low-power, backlight-free technologies for color e-book readers are an evolving field. For example, E Ink is exploring a technology called Advanced Color ePaper (ACeP), although this is currently only available as a $799 appraisal kit, and in April it launched a successor to Kaleido Plus called Kaleido 3. Another promising but yet to be realized development is NXTpaper Mid by TCL, which uses a reflective LCD screen. An alternative E Ink technology that has hit the market is DES (Display Electronic Slurry), as seen on the Reinkstone R1.

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