The Cat S60 is the very first Cat phone we've reviewed on Android Police, and it should be obvious why. These are niche devices that mainstream consumers mostly don't care about. They can take a beating, but they're also big and heavy. The S60 isn't necessarily different in that respect, but it does have one very interesting feature that other phones don't—this is the first phone with a built-in FLIR thermal camera. It would be silly to compare the Cat S60 (manufactured under license by Bullitt Group) directly to a phone like the Galaxy S7 or HTC 10, although the $600 price tag is in the same ballpark as those phones. I'll try to evaluate the S60 on its own terms and see what it offers for the rugged phone enthusiast.

Specs

SoC Snapdragon 617
RAM 3GB
Storage 32GB plus microSD card
Display 4.7-inch 1280x720 LCD
Camera 13MP rear with FLIR Lepton module, 5MP front
Battery 3,800mAh with Quick Charge 2.0
Software Android 6.0.1
Measurements 147.9 x 73.4 x 12.7mm, 222g

Design and Display

I have no doubt that if it became necessary, I could kill a man with the Cat S60.

Let's get this out of the way: the Cat S60 is a huge phone with a 12.95mm thick die-cast steel frame. It weighs 222g and feels solid as a rock. There isn't the tiniest bit of flex or creaking in the case. I have no doubt that if it became necessary, I could kill a man with the Cat S60. It's MIL-STD-810G certified, so it can take a beating without significant damage, and won't be infiltrated by dust or sand. It has a vaguely octagonal shape, but with a bump on the top where the FLIR module is. I'm not sure if this was a necessary design concession or just an attempt to make the S60 look cool. If it's the latter, I would not call it a success.

There's a lot going on with the Cat S60's design—it's actually very busy in a utilitarian sort of way. On the right edge are the volume toggles. On the left you have a shortcut button and power button at the top. I know this is a niche phone, but does that mean Bullitt needed to eschew a simple design convention like putting the power button on the right side? The only other phone I can think of with a left-sided power button is the Alcatel Idol 3. The buttons are clicky, but rather heavy and tedious to press.

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Also on the left side are two covers. One is the microUSB and the other is a customizable SOS button. It's actually very cool, if you need such a thing. Long-press the little red button behind the flap and a message with your GPS coordinates will be dispatched to a pre-defined contact. At the very bottom of the left side is a covered headphone jack as well. All the covers are very snug and feel durable.

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On the front of the S60 is where things get really interesting. There are three physical buttons for home, back, and overview. They are in the right order, despite the strange icons. They're heavily textured and have a consistent, somewhat soft click. At the top and bottom of the front panel are two gold switches marked 2m and 5m (see above). These are the water-resistance toggles. The Cat S60 can be submerged for an hour in five meters of water, substantially more robust than a typical water-resistant phone. However, you need to flip the switches to the 5M setting first. Why? These switches physically close off the earpiece and speaker (which also gets super-dusty) to prevent water from getting in. Otherwise, it's only good up to 2 meters. The drawback is that audio quality basically goes out the window.

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On the back of the Cat S60 is the fabled FLIR camera module along with the standard camera. The rear panel is made of "carbon fiber," which I think is just textured plastic. Probably the weirdest element of the Cat S60 design (and that's saying something) is the door next to the camera. Flick the switch and the spring-loaded door opens to reveal the SIM card and microSD. Was this really the most effective way to make these accessible?

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Compared to the Nexus 6p

As for the display, it's not bad. It's a 720p LCD at 4.7-inches, which is small and low-resolution by today's standards. Obviously the bezels are huge, but that's to be expected with a ruggedized device. The small size makes the resolution passable—it's still over 300 pixels per inch. The colors are a bit muted, and there's some grayscale banding visible, but it gets extremely bright. It's totally usable outside, which is exactly what this phone is for. It's almost a match for Samsung's newest AMOLED panels in that respect. The low end of the brightness range is also impressive—you'd be able to use this phone in a dark room without searing your retinas. Touch detection also works when the screen is wet or underwater.

The display is slightly recessed in the frame, so you can set the S60 down without the screen coming into contact with the surface. The panel itself also seems noticeably below the glass, which isn't the case on most newer phones. I imagine this has something to do with protecting the LCD from impacts, but as a result the viewing angles aren't ideal. There's noticeable dimming at off-angles.

Cameras

The Cat S60 has two cameras, one a standard 13MP shooter and the other FLIR's Lepton sensor. If you want a little more background on Lepton, you can check out our review of the FLIR One USB mobile camera. The internal hardware is very similar. According to FLIR, Lepton is still the best quality thermal sensor available to consumers. The main camera can be used to take regular photos with the included camera app, but it also works with Lepton in a cool way.

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As for those regular photos, they are mediocre at best. This is a utilitarian phone, so perhaps that's not surprising. The image quality is alright in bright light, but in very bright outdoor settings, the poor dynamic range causes issues. There's a lot of detail lost from bright areas clipping and bleeding into darker areas. Shutter lag becomes an issue in medium and low light. The autofocus is also easily confused in these settings. There's more noise than you get with other phones in this price range as well. I'd imagine there simply wasn't a lot of attention paid to the image processing for regular photos—the focus was on the thermal images. That's really why you buy the S60.

There's a FLIR camera app included on the phone, which boots up the Lepton sensor to pull in thermal data. A low-resolution contrast feed from the main camera is overlaid on the Lepton image (using FLIR's MSX technology). This gives you an outline of objects in the visual spectrum, making the thermal data much easier to interpret; objects aren't just blobs floating among other blobs. This is great when there's plenty of light, but in the dark you can't get a good image from the main camera. The app lets you turn on the LED in those instances, but that'll only be good for close-by targets.

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The FLIR app is similar to a regular camera app with a viewfinder, capture button, and a few settings. It's clear from using the S60 that the framerate of the viewfinder (and any video you take) is very low. FLIR says it tops out at nine frames per second, which is an artificial limit. Federal regulations prevent anything of higher quality from being sold to consumers. I've also noticed some alignment issues with the visible and thermal camera—it was actually the same for me with the FLIR One. Luckily, there's a calibration feature in the FLIR settings. This seems to work well for objects that are at least a few feet away, but closer objects still look misaligned to me. There's a manual adjustment feature in the viewfinder that can be used to fix that, but it has to be done every time you open the camera. FLIR's software has improved greatly since I reviewed the FLIR One.

It's like having Predator vision.

The default color scheme is "iron," but there are a dozen options in the app (it's like having Predator vision). They all show you the same data, but might help you interpret certain environments more easily. For example, the "hottest" filter highlights the hottest area of the image, leaving the rest in grayscale. You can also add a temperature readout to the display for point measurements, as well as high and low readings across the frame (I have these on in the examples below). This is where the FLIR camera becomes more than just something fun to play with and can actually be useful in industrial situations. FLIR says the temperature readings should be accurate within a few degrees, and you don't have to touch anything. The data is preserved for all thermal photos, so you can go back and edit them in the FLIR app to move the temp probe around.

The photos produced by the FLIR camera are 640x480 when you export them, but that's even scaled up from the sensor's native resolution. They look good overall. There's some visible aliasing of the outlines, but they're still the best thermal images you're going to get as a consumer in this form factor.

Performance and battery

While it's priced in the range of flagship phones, the Cat S60 is a little lacking in the spec department. A big chunk of what you're paying for is the thermal camera, after all. With a Snapdragon 617 and 3GB of RAM, the S60 isn't an especially slow phone. It gets the job done and most apps seem to clip along without any weird lag or hanging. Switching apps can sometimes take a little too long, and opening an app that's not already running tends to be slower than it would be on a phone with faster internals. Booting up the thermal camera always seems to take too long, though. I have to wonder if a device with a Snapdragon 820 would manage that better. There are a few benchmarks embedded below if you want to check those out.

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As for battery life, the Cat S60 is an absolute monster. The combination of the modest SoC, 720p display, and the Marshmallow power saving features allows the 3,800mAh battery to last ages. The S60 strikes me as the sort of phone people are going to use in a work environment, not lounging around for a few hours browsing Reddit. Thus, I think lighter, more intermittent use will be the norm here. With light use (i.e. using the thermal camera, some messaging, calls, etc.) I can manage over two days on the Cat S60. If I really push the device, the screen time is still upward of seven hours over the course of a day with a bit left in the tank.

The Cat S60 also supports Quick Charge 2.0 via its microUSB port. That, along with the long battery life, means you really don't have to charge this phone overnight. It'll last a few days with typical usage, and it can recharge fast enough that you can just top it up over lunch.

Software

There's not a lot to say about the Cat S60's software because it's basically just stock Android 6.0.1. That in and of itself does deserve some praise, though. Bullitt rightly realized it would be a waste of time to make a bunch of unnecessary modifications to Marshmallow. So, what you get on the S60 is almost identical to the Nexus or Motorola build of Android. The system itself has not been adapted to the hardware. The UI is unaltered, save for a few menu items that offer tutorials on the S60's features, SOS button control, and settings for the programmable shortcut button. The quick settings are bone-stock, the UI tuner is there, and the default home screen is the Google Now Launcher. Good decisions all around.

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Since the FLIR camera is handled by an app (The MyFLIR app), its features can be updated over time. There are also a handful of other apps that can plug into the camera. There is actually an API available for the FLIR camera in the S60, so developers can create new apps to take advantage of the hardware. I'm skeptical there will be a raft of S60 apps in the Play Store, though. The device doesn't really have wide enough appeal for that. The API is probably there for companies that want to develop custom tools for their employees to use.

Conclusion

Should you buy the Cat S60? Almost certainly not. This is not a phone for the average consumer, but I could see businesses buying them for employees. Almost every contractor I've dealt with was carrying some sort of smartphone in a giant ruggedized case, but the Cat S60 doesn't really need a case. It also has a huge battery and the built-in thermal camera, which could be of great value in a lot of fields. I've had immense fun playing with the S60's FLIR camera, though I don't personally have a lot of use for it on a regular basis (at least not serious ones). It simply would not make sense for me to carry this phone, and I'm sure most of you are in the same boat.

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There are a few design decisions I question, even for a niche phone. There's no reason the power button needs to be in such a weird place, and the door on the back for the SIM and microSD card baffles me. The rest of the design, while not what I look for in a phone, makes sense in the context of a Cat device. This phone looks and feels like a tool, a piece of equipment that doesn't need to be babied.

If you're especially into the whole thermal camera angle, picking up a FLIR One is probably a better deal. It's $200-250, but unfortunately it only works with microUSB phones right now. The Cat S60 should be available to pre-order this week for $599.