These ISO Glass Viewport flanges follow International Standards Organization (ISO) standards and have a flange size of NW-200. The viewport uses 7056 glass NW ISO in a one-piece assembly. This viewport replaces a blank off cap and uses a standard NW ISO centering ring assembly and NW ISO claw clamps for sealing. ISO flanged vacuum fittings are commonly used to build process vacuum plumbing and systems for industrial applications. The fittings are quick to assemble using double claw clamps and a centering ring. The Viton centering ring contains a rubber/elastomeric o-ring. The ISO standard sizes for large flanges are NW-63, NW-80, NW-100, NW-160, NW-200, NW-250, NW-320, NW-400, NW-500, NW-630. These vacuum fittings are made of corrosive resistant stainless steel.