In the semiconductor and vacuum industry, there are 13 common flange sizes that fit most equipment. As such, there are associated standard AS-568 O-Rings that fit those flanges.

This guide shows flange sizes alongside the respective 300 series or 400 series O-Ring.

Since NBR, FKM, and FFKM are the most common O-Rings for these applications, the cross section, ID, and temperature ranges are provided.