Plast-O-Matic Valves” Series PRA pneumatically controlled pressure regulator, also known as a pressure-reducing valve, maintains a constant downstream pressure from five to 125 PSI with a high accuracy over varying flowrates. The air-controlled pressure regulator is designed for highly corrosive and ultra-pure chemicals. It uses compressed air and two rolling diaphragms to control liquid pressure with greater accuracy than spring-loaded regulators. The instrument routinely handles inlet pressure up to 150 PSI. Available in a number of rugged thermoplastics, including Grade 1 Type 1 PVC, natural polypropylene, and Kynar PVDF. Elastomers are FKM or EPDM. Pipe sizes range from 1/2″ through three inches.