GoPro Mounting buckle
thingiverse
I had some issues with the available GoPro buckles on thingiverse so I made my own. Easy to print and use. -------- ~~Edit: Be careful with 3D printed mounts, they are not as robust as the real gopro ones~~ Forget that, I got a new real Gopro buckle and it broke even quicker than my 3D printed ones. 
Download Model from thingiverse
With this file you will be able to print GoPro Mounting buckle with your 3D printer. Click on the button and save the file on your computer to work, edit or customize your design. You can also find more 3D designs for printers on GoPro Mounting buckle .