Size: NW40 to Male 1" Material: 304 Stainless Steel A uniform application of pressure on the clamp insures a vacuum seal. The mating flange surfaces compress the o-ring, which is held in place by a metal centering ring, to generate vacuum seal. Male NPT to KF Adapters allow for the adaptation of a Male NPT fitting to a KF flange as a single interface vacuum component. Used to connect items with two different type flanges., Manufacturer: QGSKUSEYO