It's a GoPro hero 4 in a case and it was balanced before the shot.
YouTube video is here.
You can watch it frame by frame here. It's most noticeable around 0:29. Look at the school in the background but the shake is visible several times along the video. I think some of these units are defective.
And a slow motion video taken in the same conditions with an iPhone 7 plus on the Osmo Mobile.
Complete garbage and unusable and not because of my movements but look what happens to the frame. Distortions and jump in and out and also lots of dropped frames. Yuck.