The 100889066 Dodecagon Bolt and Nut Set includes (25) 2.0 inch 5/16-24 Dodecagon bolts, (25) 5/16-24 nuts and (25) 5/16-24 washers for use in joining thru-hole 4 1/2 inch CF ultrahigh vacuum (UHV) flanges. Dodecagon bolts feature a 12 point head style that greatly reduces the risk of seizure or breakage. 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.