This is a breathable hands free mouth mount, you put it on your mouth and bite down on the mouth piece, you then can record videos from a good height (not to high, and not to low of an angle).
Your head acts as a natural stabilizer, so you will get a more stabilized video.
It hangs the gopro just below your chin on your neck, and it is easy to move around with.
Its good for recording Surf, Long-board, Parkour, etc. type of videos.
it is very strong and wont break easily, so be careful not to break your teeth.
In the pictures, mine is longer because I'm taller and I wanted a lower camera angle, but it just gets in the way when I look down, so this model is shorter so it works well.
Amazon Basics pla
Use a Brim or Raft rather than a skirt, this will be the most efficient type of adhesion.
Make the support overhang angle "55" (if you trust your printer, "45" if you don't).
55 degrees takes way less time to print.