For connection of the  individual vacuum components there are different flange systems available: small flanges (ISO-KF) in sizes DN 10 to DN 50, clamped flanges (ISO-K) in sizes DN 63 to DN 630 and CF flanges in sizes DN 16 to DN 250. The choice of the best system depends on the required standards for example: cost-effectiveness, simple to fit and remove elements, leak tightness, high class materials or the demand for bakeable elements in the ultra high vacuum range.