This is part of the aMESS Arduino Modular Enclosure Stacking System. It is designed to fit an Arduino MEGA, RAMPS shield, and 40mm Fan.The fit on the current version seems a bit snug now that I've had a chance to print one. I'm going to add a bit more room around the edges. I also neglected to put a hole for the reset button and the fan mounts, and the standoffs in the back should not be where they are. The MEGA is only 4 inches long. I should also open up the front a bit and add a bridge across the top for support.More coming soon, including the lid!