It is an O ring that it is used most for every seal part.
With an important function part, the materials are various, too. I advise it if I talk about a use use, a condition, a purpose after confirmation on the occasion of use well.
An O ring for fixation for JISBS2401P movements
An O ring for JISBS2401G fixation
An O ring for JISBS2401V vacuum flanges
An AS568AO ring
An O ring for JISOF404 cars
An O ring for vacuums and a gasket
A large-diameter forwarding firing O ring