... or Electric Type Material:Cast Steel or Stainless Steel Pneumatic Regulating Valve For Water, Steam, Oil, Acid, Gas Size: ... mechanics theory designed according to such low flow resistance in surface flow ,large adjustable scope, Inherent adjustable proportion ... 240Supply pressure Mpa0.1-0.40.4-0.7Inherent flow characteristicsLinear ,Equal-percentage,Quick-openInherent rangeability50:1Leakage levelHard ...