http://kn-homecorner.i2p/blog/index.html
The only difference to cheapest models is, that it actually does record native 4k/60fps videos, but the quality is very bad. The picture is soft, not very detailed, stabilizer is worthless even in modes it work, distort correction doesn't correct the picture right, audio is typical bad action camera quality, battery lasts for an hour with 4k/60fps recordings, bitrate with max settings is 35mbit/s.