Miller Smith H2051B-580H Single Stage Flowmeter Regulator 50 PSI With Tubes are made of shatter-resistant polycarbonate resin and can be rotated to position desired scale for easy reading. Scaled for CO2, argon and argon/CO2 mix, and helium. Built-in Rupture Disc reduces possibility of flow tube damage due to inadvertent high-pressure surge. Must be replaced if ruptured- not auto-resetting. Precision flow-adjustment valve allows easy adjustment to desired setting Dual flowmeter regulator has a back-pressure compensated flow tube with shatter-resistant polycarbonate cover.