The 100889025 Viton Flange Gasket is used to provide a ultra-high vacuum (UHV) seal when joining two 4 5/8 inch CF flanges. This Viton CF gasket features a unique notching in the design for less outgassing than most elastomer seals. Series 88 flange gaskets are flat gaskets that are placed between two knife edges to provide a vacuum tight seal between the two CF flange faces and secured with flange bolts. Bolts should be tightened diagonally, versus sequentially around the circumference, for a secure vacuum seal. Assembly is cost effective through reuse of components and inch dimensional stubs, sockets, and tubes. The foolproof design provides leak tight joints consistently.