This mount is for Factor Ostro VAM V1 seat post, allowing you to mount a any accessory with a gopro mount
And following fastener2 x M3x5mm1 x M4x16mm
Update V2:A new version is now available, the V2 has been optimized for FDM printing, you can print it without supports.
3D PRINTING SETTINGSI suggest printing this in nylon fiber with carbon or something similar.
Use 0.2mm layer height with at least 50% infill