Williams/Bally 1" diameter blue pad used on many pinball machines.
Pad attaches to game via a nub on the back of the pad.
Williams/Bally #23-6702.
Jersey Jack Pinball #25-9001-01 & #25-009001-01.
Chicago Gaming Company #PIN-23-6702.
Barrels of Fun #000-RUB-0203-00.