A clip for holding plexiglass windows on the replicator.Print a bunch by changing Skeinforge settings to do multiples. They are small parts so they print fast. I printed mine with 100% infill. Then find some small nuts, lock washers, and bolts, drill the holes in the side of the replicator and bolt these puppies on. Tighten enough that they stay in place but not so tight that you can not rotate them when you want to.