The 100889185 Silver Plated Copper Flange Gasket is used to provide a ultra-high vacuum (UHV) seal when joining two 4 1/2 inch CF flanges. This copper CF flange gasket is silver-plated for systems that require frequent high temperature bakeout to prevent oxides from forming that could contaminate the system. 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.