From the blog

Gasket spiral wound – R

The Gasket spiral wound type – Style R gasket consists of additional plies of metal used at the start and termination of the winding process improving stability and sealing performance.

ApprovalBAM for Oxygen, TA Luft
Flange FaceFlat Face to Recess/Groove, Male and Female, Tongue and Groove
Maximum Temperature450°C / 842°F
Minimum Temperature-240°C / -400°F
Pressure431 Bars / 6251.14 PSI
Pressure Class & RatingASME , JIS , DIN