This is a chest camera mount made by GoPro. It was included as an accessory when I purchased the main unit used. I have never used it, but I don't know how often the previous owner used it. However, as far as I can see, the straps don't seem to be stretched much. As a bonus, I'll include a neck mount of unknown manufacturer (last photo). Since it's not something that's easily damaged, it will be simply packaged in a plastic bag and placed in a cardboard box.