This thingy allows you to attach your GoPro Action Cam to a standard camera tripod. The part has an embedded 1/4-20 UNC thread for the tripod attachment and only requires an M5 nut for the thumb screw that comes with the GoPro camera. The nut can be optionally epoxy-glued to the part to make it permanent.

I printed the part in ABS and used acetone vapour bath to give the part a professional finish.