This KF10-KF16 Centering Ring Adaptive vacuum fitting follows KF standards. They are commonly used to build foreline vacuum plumbing and process systems. They are often called quick flange fittings because they are quick to assemble. A circumferential clamp and centering ring form the vacuum seal between the connecting flanges. 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. They are made of corrosive-resistant stainless steel with Viton® O-Ring. Viton® is well known for its excellent resistance to heat (400°F/200°C) and to aggressive fuels and chemicals.