Multi-purpose electrical connection box for locating on/off switches, LEDS, etc.. The big holes on the side fit standard North American electrical box cable clamps. I left one box with no holes so that you can drill holes for your own project and one of the lids has a stiffening rib in the middle that can help protect a switch from impact.
We build 3D printers!
I've been following the RepRap project since about 2008, and building 3D printers since 2011. We started with a Techzone Mendel, and then I used it to print the parts for a Prusa version 1 which morphed into a verison 2. I used that machine to print up a pile of Prusa i3 parts. The cycle just keeps going!