Built is a 3.7 V / 810 mAh Lithium-Ion battery labeled 423,450th This can be removed even through a door on the back of the device and thus could be exchanged. There is also a storage for the USB dongle. Rechargeable battery is a mini USB port on the top of the unit. This works well, a suitable cable is included. The keyboard consists largely of plastic and is therefore pleasingly light, acts nevertheless sufficiently well finished.
The actual keyboard is surprisingly good. Of course I would want to enter a long texts with this device, but by brief entries in a browser or search queries in a media center or enter a few brief aims to write at a Raspberry Pi sometimes code, that's pretty much perfect. With just one dongle and controller has united all the necessary input devices and always at hand. Especially the two keypads in addition to the touchpad did it to me with this, because you can navigate with this very easy through menus and control music and video, including the volume.
One must learn once on the layout and operation of this keyboard used because they naturally differs mainly by the small size of a normal keyboard layout. But I would not have thought that writing after a short but works so well.
There are also a few points, the less I like. Taken together, these things are rather negligible, because they hardly affect the otherwise excellent functionality. The button for the space bar is wider than the other keys still can be triggered only by a pressure in the middle. Which interferes with the input a little. Furthermore, I disturb me at the touchpad a little. This is primarily as a mouse and works very well. Even gestures (such as two-finger scroll) facilitate control and are especially while browsing the Internet very convenient. However, this is a bit small and additionally deepened. This is a little inconvenient to use.
Conclusion: The unit is ideal for a Raspberry Pi with installed Media Center. However, for example, the control under Raspbian is pleasant enough for many applications. The device combines the control system with mouse, touchpad and keyboard in a single device, without that I would miss something now. I'll use it now very happy with a Raspberry Pi 2 and am very satisfied. Recommended!