Model originally uploaded to Thingiverse at https://www.thingiverse.com/thing:4767623.

I made this to mount my Apple TV 4 HD on to the wall mount bracket my tv mounts to. It slides on to the rail and has a screw that goes through it to keep it from sliding back off. Files are orientated to print without supports. Included is a drawing with dimensions for the rail this will fit over. it is not a tight fit. There is a slight bit of slack built in to both the rail block and the holder for the Apple TV itself. Just print both and then glue together. Screw hole is sized for an M3 socket cap head screw and will self tap the threads. No nut needed.