Custom mount to interface the GoPro mounting system with LEGO Technic parts.
This part was used in the LEGO MINDSTORMS GoPro Mount showcased at World Maker Faire 2015 in New York. See the picture above or http://08milluz.com for more details.
Note: In some programs, the .STL comes out 1/10 the size. You can just scale up and it should be fine.
Scaling accounts for ABS shrinking.