The Harris® Model 356 dual flowmeter regulator for use with Argon (Ar), Helium (He) is capable of providing two separate independent flows from one common gas source. It is equipped with two Model 55-2 flowmeters that can be set at different flow rates. It is ideal for back purging, trail purging and/or other dual applications. This model features sensitive needle valves for fingertip control and durable, easy-to-read, flow tubes and covers. It is equipped with a tamper-proof, self-reseating, high pressure relief safety valve. The regulator features a brass body and painted zinc bonnet for longer service life, and a neoprene diaphragm for better pressure control. It has a 2" brass dual scale gauge and one-piece encapsulated seat design with internal filter to protect the PTFE Teflon® seat from particulate contamination. It has a 5/8" - 18" (Female) outlet connection. This model is UL® listed.