White pinball rubber O-ring measures 1-1/2 inch (38 mm) Inner Diameter and 2 inch outer diameter.
Cross sectional diameter is standard 3/16 inch (4.7mm) with Durometer 40 hardness.
Reference:
Allied Leisure 264-8-103Atari 006127-07Bally R-521-2Bally R-141Capcom RB00108-08Chicago Coin Machine 6052Gottlieb A-10220Jersey Jack Pinball (JJP) 25-002003-24-09Marco 38-1500Midway 0017-00041-0644Sentinel 644031-1Sega/Stern/Data East 545-5025-07Stern S.E.I. 7A-120-150Stern S.P.I. 545-5348-57Valley 66-380-004Wico 25-0070Wico 19-008600Williams 23-6304