The improved plastic gauge guard is designed for liquid processes to 250 PSI, which is 15 PSI higher than any previously published plastic pressure rating, according to the manufacturer. Gauge guards, also known as diaphragm seals or instrument isolators, are designed to protect gauges and other instruments from corrosive liquids by the flexible, durable diaphragm in the guard, which serves as a barrier between process fluid and the instrument. The flexing characteristics of the diaphragm and its large sensing area provide immediate response to even small changes in pressure or vacuum and are accurate to 3 percent. Series GGM Gauge Guards are available with or without gauges in PVC, Polypropylene or PVDF with PTFE or FKM diaphragm. Instrument connection sizes are 1/4" or 1/2" NPT with 1/2" system connection.