These are Ultra High vacuum system components - highly specialized for scientific & Industrial vacuum applications.

New Old Stock - I believe these are Nor-Cal Products parts - were found with other specialty parts such as valve flange pipe Nor Cal parts - these will all be listed and available soon as well.

These Parts have been in long term storage - Individually sealed. Brand New.

NOTE: O-Rings are NOT included with centering ring. A = 8.26”

***ISO 200 centering rings are commonly used to build process vacuum plumbing & systems for Industrial standard & High vacuum applications.