A tray to mount your Sanguinololu to the base of your Prusa with cover that can hold a 40x40mm fan.
I have printed it myself in black PLA with 30% interior fill. The studs to mount the PCB should not get to hot wile printing (use cooling or get your towers setting right) or they need some filing/ sending after the print.
The one I've printed fits perfectly. You can mount it under the printbed or outside the frame.