These vacuum Co-Seals are designed to seal ISO flange fittings and are made of a polymer-supported nitrile O-rings, which is suitable for high vacuum down to the 10-8 Torr range. They represent a major advance in the method of sealing NW and ISO flange connections. The seal design eliminates crevices and trapped gas volumes. When fitted, the inner face of the Co-Seal is directly exposed to the vacuum system, eliminating any crevices or trapped volumes, which can generate gas bursts and inhibit pump-down. 

Unlike the regular centering ring and O-ring, the NW Co-Seal is fully restrained externally. These Co-Seals are available with either nitrile or fluoroelastomer seals. They can be used for either ISO-F bolted or ISO-K collar flanges, the cut-outs around the external circumference of the Co-Seal are positioned so that the securing bolts or claw clamps centralize the Co-Seal precisely. These Co-Seals are for ISO NW-100 flanges and contain a Nitrile seal and are sold as one each.