Stainless steel protector set for the capture ball holes on William's Terminator 2 pinball machines.
The rings are designed to sit down into the hole protecting the edges of the hole. Take clear bathroom silicon and apply a bead under the lip of the ring and press into hole fitting it correctly. Some of the silicon may squirt out around the edge. This is normal. Take a paper towel and wipe up the excess silicon. The silicon does several things. Firstly, it provides an additional cushion for impact. Secondly, it holds the ring in place during game play. Should the ring ever break free just strip the old silicon and reinstall.
Another great product from Mantis Amusements!