On Monday morning, I did something I often do when testing a new device: I took it off the charger to see how long it’ll last under regular use. This time around it’s an obscure phone called the Doogee S80, and at the time of writing this on Tuesday afternoon, the battery has just hit 30 percent left.

Not bad, right? What if I told you I was talking about last Monday?

The S80 belongs to a niche class of Chinese phones with really, really big batteries. This particular unit is built around a 10,080 mAh battery; for comparison, most current Android flagships come in between 3 and 4,000 mAh. Doogee claims it’ll be good for 76 hours of continuous video playback, 136 hours of talk time, and 1,308 hours in standby.

I quite literally do not have the time to test those claims directly, but what I can say is that you probably can expect about a week of regular use out of the S80. As I said, I’ve been using my unit for eight days, and while it admittedly hasn’t been a particularly hardcore week for me in terms of phone usage, I’m still impressed with the endurance.

S70: A smaller option If the S80 is a little too much, Doogee’s S70 is a very similar phone but with a little more than half the battery capacity (5,500mAh) and thickness (13.5mm). It also has a snap-on gaming controller similar to the Xiaomi Black Shark’s, with a decent analog stick, a terrible D-pad, and some usable shoulder buttons. Again. though, I wouldn’t expect much out of the Helio P23’s gaming performance. The S70 is probably a more practical compromise for most people, but I have to think if you’re going out of your way to order either of these phones, you’d need the best battery performance possible. In which case, it’s better to go big or go home.

What’s the catch? Well, if you’ve ever wished for phone manufacturers to stop focusing on thinness and just put bigger batteries in their devices, the S80 offers you an opportunity to put your money where your mouth is. This is a ridiculous tank of a phone, somewhere between Nolan-era Batmobile and potential murder weapon in Clue. You can put it in your jeans pocket, but you won’t want to. It weighs 398 grams — or almost a pound — and is 21.2mm thick — or almost three iPhone 8s. It feels like it could survive a fall down a mountain.

Which, to be fair, is one of the intended use cases for a device like this. It has a port for a walkie-talkie antenna and a dedicated push-to-talk button, and is rated for IP68 and IP69K environmental protection. Coupled with the long battery life, this is a phone designed to be taken on multi-day hikes or used on construction sites rather than at an Instagram-friendly cafe.

You can use it as a regular phone, of course — the 6-inch 18:9 1080p LCD is mostly fine, the camera is passable, and it actually feels kind of nice to hold something so chunky in the hand. It’s even nicer not to have to worry about battery life in the slightest.

But performance out of the MediaTek Helio P23 processor is noticeably laggy, even though the phone runs something very close to stock Android 8.1 Oreo. And it’s a good thing you rarely have to charge this phone, because dealing with the rubber flap that covers the USB-C port is infuriating. (It does have wireless charging, surprisingly, which is a welcome — if slow — option.)

Doogee is far from the only small Chinese company making phones like this. Oukitel, Ulefone, Blackview and others all have similar devices with comparable specs, and I’m sure they last just as long. The S80’s main point of differentiation is its walkie-talkie antenna, as far as I can tell.

I’m not a survivalist, jungle explorer, or construction worker, so I don’t really have a need for a phone like this. I rarely worry about battery life on my regular phone, and for times when I do, I’d usually rather just use a USB-C PD battery pack. But it is definitely cool to see an all-in-one solution that more or less functions as a competent modern smartphone, and I think there are people with lifestyles more extreme than my own that would consider the Doogee S80 to be $379.99 well spent.