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.printinstall fan: if you want a fan glue it under the cover at the marked area. If you want to use screws you can drill the holes for them through the cover and use 4 x m4 to mount the fan. Glueing will give a nicer cover.decide where you want the trayglue the hook under the tray so that the hook is over the rod parallel to the printbed and the lip resting on the rod that is attached to the z-axismount the Sanguinololu on the bottom with the self tapping screws to secure top and bottom (you can also use m3 nut and bolt to secure top and bottom but you have to drill the holes through the top)put one or two cable ties through the holes of the lip to secure the tray