KF Flanges are genderless by design and use a rubber/elastomeric o-ring in a centering ring to seal the connecting flanges. The flanges are held together by a clamp that surrounds the joined flanges. By tightening the wing-nut, lever, bolt or thumbscrew, the clamp creates a leak-tight connection sealing the flanges. Flanges are sized by the largest nominal ID tube welded to it. KF (QF) flanges are also available in Aluminum or Brass for general applications.