White O-ring with 3/4 inch (18 mm) inner diameter.
Reference:
17-41-642
Alvin G RBR-019
Atari 006127-04
Bally R-137
Bally R-521
Data East / Sega / Stern 545-5025-04
Game Plan 08-30015N
Gottlieb A-10218
Jersey Jack Pinball (JJP) 25-002003-12-09
Marco 38-0034
Stern S.E.I. 7A-120-400
Stern S.P.I. 545-5348-54
Wico 19-008300
Williams 23-6301
Zaccaria VA5012