The 100889150 Thru Hole Flange Bolt and Nut Set is designed for joining two thru-hole 2 1/8 or 2 3/4 CF vacuum flanges. This bolt set includes (25) 1/4-28 flange bolts that are 1.38 inch in length and (25) 8-32 nuts and washers. Series 88 CF components are joined by inserting a gasket between the two flange faces, then securing the assembly with 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.