
GoPro Chesty Chest Mount Harness: This GoPro chest mount for your camera makes it easy to capture exciting video and photos from the level of your chest. Perfect for any activity where you want a lower-than-the-helmet view of the action. 
A: The harness is completely compatible with the Hero 5.
Q: Will this work with any GoPro camera
A: Yes, the harness mount will work with any GoPro.
Q: Is this compatible with Hero6?
A: Yes
Q: Will this work with the gopro hero 3?
A: Yes. This harness will work with any gopro camera that uses the traditional gopro mount system.
A: I don't know the measurement size but should be fine for a 9 year old. I've used it while running and training dogs. I'm also using it this summer on a disney cruise and roller coasters.
A: Works just fine in water and is even washable. To use the floaty back door you need to use extension links or the camera is only gonna point down. Other options might be the head piece or a mount on the jet ski
Q: Can I cliff jump with this on without it falling off?
A: yes, make sure you adjust it to use size