Here's what the box says:
REMOTE SHUTTER BT
BT Selfie Shutter for Smartphones
MT5507 V 1.0
* Selfie remote shutter
* Bluetooth 3.0 wireless communication
* Frequency: 2.4GHz-2.4835GHz
* Silicone puch to install on selfie stick
* Communication distance: up to 10 meters
* Power switch
* Power: lithium battery CR2032
* Dimension: 51x33x10 mm
* Compatibility: iOS 6.0 and higher, Android 4.2.2 and higher
* Weight: 11g
The battery is included in the package (CR2032L)
Be careful, the battery cap, on the device, is kinda hard to remove and place back - don't pull up(or you can easily break the two pieces of flimsy plastic that are within, holding the cap tight on the side of the device); instead slide the cap to open it - you may need to push a little in the middle of the device too(because that's what's preventing the cap from sliding).
The manual says: "Installation: Use your smartphone and download application "Camera 360" from Google Play (Android platform) or App Store (iOS platform).
Next, switch power button on the device (status LED will blink every 1 second) and then search for Bluetooth devices in your smartphone. When you see "AB shutter" device, click option to pair device. When pairing is successful status LED will be off.
Notice! When device is connected it will replace standard screen keyboard in your system, if you want to write SMS for instance, please power off device firstly.
Using the device: Run "Camera 360" application, for android devices use "Android button shutter" to take a photo, for iOS devices use "iOS shutter button" release. LED status will be on whenever shutter button is pressed."
Well, that's good to know! Am I right? high five :)
In my case the included battery had 2.92V and was apparently not good enough to even power on the remote, so I put a new one, CR2032(without L) which had 3.31V and what I can say is that I didn't need to download the "Camera 360" app (or, is this the same app as the camera app? I don't know, probably not) when using the remote with "HOMTOM HT16 KÉK OKOSTELEFON" and that the iOS button, on the remote, was the only button which consistently worked to take pictures with either front facing or back facing cameras; the android button on the remote, sometimes opened camera Settings instead of taking a picture, and sometimes it toggled the V sign setting which is displayed on the screen; this is probably why the recommend using the "Camera 360" app, my guess.