The fan base that comes with the Filastruder is made of wood, and the four nuts that are trapped in the wood can be dislodged easily. This part replaces that wooden part. In theory, you can slip four nuts into the slots and then use this part exactly like the wooden part. In fact, when I printed it, all of the screw holes were just a littlt too small. I drilled out the four fan mounting screw holes, but left the other four side holes small, and just screwed the side mounting screws directly into the plastic. I have included the Sketchup model in case you want to tweak it