... price and quality. Pneumatic Diaphragm Steam Control Valve(150Lb, 300Lb, 600lb,900Lb,etc) Features:Top- ... Diaphragm With nylon fabric nitrile rubber Springs 60Si2Mn Valve Stem 0Cr18Ni9, 2Cr13,304,316Ordering information When ... Pressure, Temperature, Viscostiy or Acidity and Alaline )3. Valve Action (Air-to-close or Air-to-open ) ... . Pneumatic Diaphragm Steam Control Valve(150Lb, 300Lb, 600lb,900Lb,etc)