GoPro mount

Good day to all!

Wondered GoPro camera mounting directly under the wing.
Once saw a video the guys produced a great mount for camera under the wing (the pilot can be seen from above). Attachment in the case consisted of two parts, round, one of which was placed interior of the wing, and the second with the attached camera was attached to it from the other side (the outside of the bottom of the wing) with the magnets.

Maybe someone saw something like that? If you have a video will grateful :)

Thank you! Denis.