Our ISO-KF vacuum flange fitting and component system is a modular, building block method for creating 0.75 to 4 inch vacuum piping systems. Series 31 ISO-KF vacuum fittings provide several advantages. They use standardized dimensions allowing ISO KF elbows, tees, crosses or valves for a given size to be interchanged. ISO-KF flanges are also "sexless" and the seal is symmetrical so components can be rotated. The ISO-KF vacuum flange system allows the building of high vacuum systems quickly, without welding or brazing and supports quick and easy cleaning or modification of your vacuum system.