CF-style vacuum flanges and fittings are the standard for ultrahigh vacuum (UHV) applications. They use a copper flat gasket placed between two knife edges to provide an extremely leak-tight vacuum seal. Mating flanges have identical profiles, eliminating the need to store two types or worry about compatibility. Made with very high purity stainless steel and meticulous cleaning procedures, Series 88 CF components are suitable for use in the ultrahigh vacuum applications down to 10^-13 Torr pressure and in temperatures from -196° to 500°C. The material characteristics of the flanges, seals, screws, and nuts are selected to provide high performance throughout a wide temperature range. Rotatable and nonrotatable flanges in sizes from 1-1/3 to 4-5/8 in. are available with several bore sizes to fit a wide range of vacuum tube diameters.