This is a holder for Arduino Mega 2560 and RAMPS which comes with a quick release. The Arduino circuit board simply clicks into place and can be released by pressing the hook. There are also three screw holes with embedded nuts for screwing the board down, although it's not absolutely necessary. Even the complete RAMPS assembly is held correctly.
There is also a fan holder:
https://www.thingiverse.com/thing:2530995 The mounting device is intended for RAMPS boards on a 3d printer, but will serve any application of an Arduino Mega 2560. If you want to mount the device to an alu profile frame, see:
http://www.thingiverse.com/thing:2169986 The stl file already present presents the next step with more support pillars and additional ventilation for the voltage regulator on the Arduino.
This part is used in my Prusa i3 Master Rework:
Prusa i3 Master Rework The product was designed by
BensHacks