The phone's dual-SIM tray is along the right edge, just above the power switch. The compromise here is omitting an SD slot in favor of the second SIM tray; with 64GB of storage onboard and the phone's unlocked availability on three continents, that may be a reasonable tradeoff.
On the left edge is the volume rocker. Above that is a three-position slider switch that controls Android's notification functions: all, priority or silent, making the OnePlus 3 the only high-end phone other than the iPhone with a physical mute button. The switch is textured so you can find it quickly in your pocket or in the dark, a thoughtful touch.
There's an oval fingerprint sensor on the phone's chin. The speaker, microphone, USB-C port and headphone jack are all on the bottom edge.
The front camera is an 8MP unit that can do 1080p video at 30fps. The main rear-facing camera is a Sony 16-megapixel unit. It can shoot 4K video at 30fps, has electronic image stabilization and supports RAW images. There are several shooting modes: slow motion, time lapse, panorama and manual. The camera allows you to set separate focus and exposure points manually; I'm not sure I've seen that on other smartphone cameras. Image quality was OK, although other more expensive phones -- the Galaxy S7 jumps to mind -- do a better job in low light.
The OnePlus 3's non-replaceable battery stores 3000mAh, and it took the AnTuTu battery test about four hours to drain it -- about the same as the others I've benchmarked. The OnePlus 3 can charge to 100% in about 90 minutes using an included fast-charging cable they call Dash Charge. The bad news is that the Dash Charge uses a technology other than Qualcomm's increasingly common Quick Charge, so you need to use the OnePlus cable to charge at that speed. Without it, charging takes about an hour more -- which is still not bad. The phone doesn't do wireless charging.
OnePlus 3 has a lightweight skin over Android Marshmallow (6.0.1) called OxygenOS. It's pretty unobtrusive and has some nice add-ons. You can put the navigation buttons on the screens or on the phone's chin on either side of the fingerprint sensor, and you can swap them to account for handedness. The Home, Recent and Back buttons can all be programmed to respond to long presses or double taps. And you can have the phone wake by tapping the screen twice, open the camera from sleep by drawing an "O" with your finger on the screen, toggle the flashlight with a "V" and pause music by swiping downward with two fingers.
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