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World’s thinnest phone is here, but it’s not the iPhone 17 Air or Galaxy S25 Edge

Side profile of Tecno Spark Slim.
Tecno

The year 2025 could very well mark the arrival of super slim phones. Samsung has already given us a glimpse of the Galaxy S25 Edge, and could launch it as soon as April. Apple, on the other hand, is heavily anticipated to launch an iPhone 17 Air model later this year.

It seems a relatively unknown brand will beat them to the game.

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Tecno has today announced the Spark Slim, a phone with a thickness of just 5.75mm. Interestingly, it seems this phone isn’t a one-trick pony, because the internal hardware is also fairly powerful and puts it firmly in the upper mid-range category.

Now, before we get into the details, here’s the disclaimer. Tecno says the Spark Slim is a concept device. That means it’s merely an innovation showcase for now, and there is a 50-50 chance that it will never make it to the market as a commercially available product.

What’s inside this sleek machine?

Side profile of Tecno Spark Slim compared with a pencil.
Tecno

Tecno says the Spark Slim will feature a dual camera setup at the back that relies on two 50-megapixel sensors. Over at the front is a 13-megapixel snapper for selfie and video-calling duties, slotted neatly in a punch-hole cutout on a 6.78-inch curved OLED screen.

The display panel sounds quite impressive, as it offers a 1.5K resolution and 144Hz refresh rate, one of the best that the industry has to offer. Tecno is also touting a peak brightness figure of 4,500 nits for the screen, roughly double compared to the iPhone 16 Pro Max.

Powering the phone is an undisclosed octa-core processor. Unfortunately, the company has not shared any details about the RAM or storage figures, either. What’s truly surprising, though, is the battery capacity.

Rear profile of Tecno Spark Slim concept phone.
Tecno

Tecno says the Spark Slim will come equipped with a 5,200 mAh battery, which is nothing short of astonishing. For comparison, the Samsung Galaxy S25 Ultra is 8.6mm thick, but offers a smaller 5,000 mah battery.

The charging stack is no slouch either. Tecno is claiming a peak wired charging output of 45W, which is far ahead of what Apple has to offer, and matches the latest and greatest phones from Samsung.

Tecno will share more details about the phone at MWC, which kicks off next week. Digital Trends will be on the show floor, and we are expecting some hands-on time with the device, assuming Tecno has some working prototypes to show off. Stay tuned for that.

Nadeem Sarwar
Nadeem is a tech and science journalist who started reading about cool smartphone tech out of curiosity and soon started…
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