Holds six batteries for my Hero 10 and 12. Honestly, there are probably cooler GoPro battery holders on here, but I made this one for myself to fit in with my other rechargeable battery holders. I started using these for some camera batteries and found that I really liked being able to see what's charged and what's dead by the orientation (electrical contacts in for charged, out for dead). So yeah...odd disclosure aside... :)

I printed mine in PETG with an 0.8 nozzle on 0.64 layers.

If you want some additional info, and/or to check out the other variations, you can find it here.

Or if you want to brave my ugly CAD, the files are available on OnShape here.