"Style R" is the most common RTJ gasket type. R type ring joint gaskets are available in oval or octagonal cross-section and manufactured according to API 6A and ASME B16.20 to suit API 6B and ASME/ANSI B16.5 flanges.
This type of RTJ gasket is machined to tight manufacturing tolerances to ensure correct installation with standard ASME B16.5 and API 6B ring joint faced flanges. "R style" oval and octagonal RTJ gaskets can seal pressures up to 6.250 psi by ASME B16.20 and up to 5.000 psi according to the API 6A pressure ratings.