This thing is a lightweight, open, rear-loading clip-in frame for the GoPro Hero 3. The camera can be removed from and returned to the frame without moving the mount or removing the frame. But with access to all the buttons, mics, connectors, SD card and battery you can completely service the Hero 3 while in the frame. The bottom, being closed, does not provide access to the battery on the Hero 4, but the open back should allow usage of the display screen. (I don't have a Hero 4, so I can't say for sure.) Slots on the retainer clips allow for an optional Velcro strap or zip tie to fully secure the camera. A faceplate covers the face of the camera to prevent the shiny silver surface from reflecting into the image off a window. I cannibalized some parts of http://www.thingiverse.com/thing:507061 for this, but the rest I created in Lightwave Modeler and exported to STL.I printed this just fine with 100% Fill Density and otherwise mostly "normal print quality" settings on a new Ultimaker 2. Print time was just under two hours. The overhang bridges on the slots were a bit ragged and could maybe use some supports. But as the result was totally functional and better than expected I let it be. I sanded the front of the faceplate to remove the gloss of the plastic and present a more matte finish to reduce glare when used behind glass.