Toggle Clamp with Cotter Pin for KF50 Flange Size, Aluminum. The self adjusting clamp locks in a positive method. A cotter pin can be inserted to prevent accidental release of the toggle lever. This toggle clamp is excellent for quick frequent installation or removal. A circumferential clamp and centering ring form the vacuum seal between the connecting flanges (please see top right figure - click to enlarge). The centering ring contains a rubber elastomer o-ring. The standard sizes for quick flange fittings are KF-10, KF-16, KF-25, KF-40, and KF-50 with flange sizes NW-10, NW-16, NW-25, NW-40, and NW-50, respectively. They are made of aluminum.