This cover snaps on to shield the terminals on the large switching power supplies (anyone know a classification name for the this PS case type?)The open terminals on these power supplies are very dangerous. Print out a cover and snap it on so you don't turn into a crispy tart.Licensing -Parts and files: GPLv3 -Images: CC BY SA Print. Make sure your PS is unplugged. Put in your wires and tighten them. Snap on the cover. Plug in the PS.