Kurt J. Lesker Company | ISO HV Flanges Technical Notes | Vacuum ...
ISO HV Flanges are universally sized by the nominal (in, mm) of the largest tube that can be welded to the flange. The standard sizes are: 63, 80, 100, 160, 200, 250, 320, 400, 500, and 630. The ISOK is convenient and has the smallest flange for any given tube The ISOF offers greater strength when used as a structural element.