This two-stage stainless steel, high-purity regulator has been designed to provide precise pressure regulation for the Airgas® EPA Protocol Mercury Standards. The two-stage body, diaphragms, internal carriers, internal compression members, 0.06 Cv poppets, conical compression springs, 1/4" compression fitting and CGA-660 nipple are all passivated using a proprietary coating. This unique coating mitigates the chances of any level of mercury attaching to the internal wetted components of this specialty regulator. The result is a two-stage pressure regulator that will not hold back or alter any level (PPM or PPB) of the mercury standard. The internal threadless seat design of the two-stage stainless steel regulator is the same as used in our high-purity Y12-C445 series. The convoluted Hastelloy® C-22 diaphragms provide excellent regulating characteristics and allow for internal vacuum purging. An outlet 1/4" compression fitting is provided to maintain optimum system purity.