The 4pcs set comes with 3pcs for the main flippers and 1pc for the mini playfield. I sculpted the skulls to match with the ones that we designed for the Axl figure in the game. They are cast out of bone resin and given a brown/black wash like the originals. They attach to the top of the flippers via VHB tape. We recommend that you clean the tops of your flippers with rubbing alcohol before install.