Holding it for the first time, I caught myself double-checking if it even had a battery inside. That’s not a joke. It’s so light (just 166 grams) that the mind immediately questions what it’s touching. But after spending a few days with it — using it for calls, music, scrolling, and even a bit of gaming — I can safely say: this thing is real, and it’s surprisingly practical.
Design: The First Thing You Notice Is How Little There Is to Notice
Let’s start with the obvious. 5.75 millimeters. That’s not a number you can easily visualize until you hold the phone. It’s roughly three credit cards thick. You could slide it between the pages of a magazine and forget where you put it.
TECNO’s engineers, it seems, were on a mission to make a statement — and they succeeded. The company even admitted that early prototypes were too light. Users didn’t believe there were real components inside. So TECNO actually added weight to make it feel more like a “phone.” It’s the kind of ridiculous yet believable engineering anecdote that makes you smile.
Despite its size, the TECNO (SPARK) Slim doesn’t feel fragile. The recycled aluminum frame combined with a stainless-steel backbone gives it a surprising stiffness. There’s also a ceramic back option — it’s cool to the touch and resists fingerprints. It’s one of those materials that feels instantly premium, even if it’s understated.
Visually, TECNO made a smart move. Instead of chasing the giant camera island trend, they went for a horizontal, pill-shaped camera module that sits nearly flush with the body. Clean. Balanced. Confident.
Display: Bright Enough to Shame Some Flagships
When I turned on the 6.78-inch curved AMOLED display, I had to squint — not from disappointment, but from brightness. TECNO claims a peak of 4,500 nits, and while I didn’t have a light meter to verify it, I can confirm it’s extremely bright. Even under midday sunlight, the screen remained legible.
This panel runs at 1.5K resolution (2712×1224) and supports a silky-smooth 144Hz refresh rate. Scrolling through Twitter (or X, if you prefer) felt more fluid than on some $1,000 flagships.
Videos look punchy without oversaturation, and the curved edges subtly enhance immersion — not in a gimmicky “waterfall” way, but just enough to make borders disappear. The 20:9 aspect ratio feels natural for social media and one-handed use, though it might feel tall for landscape gaming.
There’s also HDR support, which, combined with that high brightness, makes YouTube and Netflix playback genuinely enjoyable.
Battery: The Real Magic Trick
Now, the big mystery — how does a 5,200mAh battery fit inside a 5.75mm frame? I asked the same question. TECNO says it uses a battery that’s only 4.04mm thick with 800 Wh/kg energy density. That’s industry-leading territory, achieved without silicon additives.
In my real-world testing, the phone comfortably lasted a full day of moderate use — about 6.5 hours of screen-on time, with Wi-Fi, 5G standby, and occasional camera use. Not bad for something this thin.
It supports 45W fast charging, which took it from 10% to 70% in roughly half an hour. That’s impressive, though the phone warms up slightly during charging (understandably so, given its size).
There’s a subtle irony here: a phone this slim offering better endurance than bulkier mid-range rivals.
Performance: Lean, but Not Weak
Under the hood, the TECNO Slim runs an octa-core Mediatek Helio G200 processor. My unit had 8GB+5GB of RAM and 256GB of storage. Not great, not terrible 😉
In daily use — messaging, browsing, watching videos — it never stuttered. Apps launched quickly, multitasking felt snappy, and even moderate gaming was fine. RAID Shadow Legends at medium settings ran without serious frame drops.
There’s even an optical fingerprint sensor built into the display, which is reasonably quick, though face unlock was faster in good lighting.
Cameras: Small Body, Big Confidence
Here’s where I expected compromise. How do you fit good optics in a 5.75mm phone? Yet TECNO somehow pulled it off.
The dual 50MP rear cameras produce genuinely decent results in daylight — sharp edges, balanced contrast, and accurate colors. Low light is where physics inevitably pushes back; noise creeps in, and details fade a bit. Still, the results were better than I anticipated.
The 13MP front camera is competent. Skin tones look natural, though highlights can blow out in direct sunlight.
Then there’s the interactive light band around the camera — it pulses subtly during notifications or charging. It’s a gimmick, perhaps, but a charming one.
Ergonomics and Daily Life
After three days with it, something unexpected happened — my thicker iPhone started feeling clunky. The TECNO Slim redefines what “portable” means. It slips into jeans without a bulge, disappears in a jacket pocket, and somehow makes every other phone feel oversized.
Typing on the curved screen took some getting used to, and I did accidentally touch edges while scrolling a few times. Still, those were minor annoyances compared to the overall comfort.
One subtle drawback? Heat management. During extended gaming or charging, you can feel warmth spreading through the thin frame. The ceramic back helps, but physics has limits.
Durability Concerns — But Not Dealbreakers
I didn’t dare bend-test it (that would’ve been irresponsible). But I did accidentally leave it under a stack of papers overnight. It survived — perfectly fine. The stainless-steel structure seems to do its job.
Final Thoughts: Beauty in Restraint
The TECNO Slim isn’t just another mid-range smartphone. It’s a design statement, a technical achievement, and, in a strange way, a nostalgic reminder that innovation can still surprise us.
This device doesn’t scream for attention; it earns it. It’s quiet, purposeful, and almost poetic in execution. The fact that TECNO managed to fit a 5,200mAh battery, 144Hz AMOLED display, and dual 50MP cameras into a phone barely thicker than a pencil — that’s extraordinary.
Would I recommend it? If you value design, portability, and novelty — absolutely. If you want a phone that looks like it time-traveled from the future, this might be it.
What Stands Out Most
- The world’s thinnest phone at 5.75mm
- Massive 5,200mAh battery
- 6.78-inch AMOLED, 144Hz, 1.5K resolution
- 45W fast charging
- Dual 50MP cameras
- Android 15 + 5G, Wi-Fi 7
- Unibody aluminum/ceramic design
Verdict
And perhaps, just perhaps, that’s the spark (sic) we’ve been missing. See what I did there? 😉