I wanted to mount my GoPro Hero 8 to my backpack for mountain bike riding but the combination of a Peak Design Capture Clip with an Arca Swiss plate and a GoPro tripod adapter was incredibly heavy and dug into my upper arm an chest.

I needed something lightweight that wouldn't injure me in a crash and (hopefully) breaks on impact.

This is an incredibly simple design with 2 plates and a little angle adapter to adjust where the camera is pointing.

You will need 2 sets of this 3D-printed bolt (socket type) and nut: https://www.thingiverse.com/thing:193647

The existing M5 bolts that came with you GoPro will work fine to secure the angle mount and the camera itself. You'll need 2 M5 nuts.

I added a layer of stick-on rubber to the back plate so the whole assembly wouldn't slide down the strap with aggressive trail riding.