According to DIN 16966-T6 Datasheets | FRP Backing Rings | RotecGRP.com

Rotec FRP Backing Rings
(According to DIN 16966-T6)

Product Datasheets

#
1

Drilling Standard
ANSI B16.5 Class 150

DN (mm) Range
200 - 600

Pmax (bar) Range
3 - 6