Gentec 152 Series is Designed for medium duty gas welding, cutting, and heating applications. These regulators are ideal for industrial applications, farm repairs and laboratory testing, etc. CGA520, 9/16in-18LHM, Gas: Acetylene. Forged brass body and housing cap Delrin cap bushing for smooth adjustments Self re-seating external pressure relief valve on oxygen, inert gas, and air models Sintered bronze inlet filter Stem-type seat assembly for more reliable performance 2in gauges for easy reading 2in diaphragm Steel Gauge Protectors are color coded: green for Oxygen GP21X and red for Acetylene GP21Y Weight: 2 lbs 11 oz UL Listed