Ready for installation on existing ANSI or DIN Standard flanges, this bolt-on unit consists of a base with raised face flanges to fit standard ANSI class 150 flange nozzles. Sizes range from 2 to 8 inches and all conforms to ASTM standards. The glass disc, either borosilicate or quartz, is clamped in place by a gasketed glass retainer held by threaded bolts. Light and wipers are available as options.