The 3590ST model was a common variant in this series. Its technical highlights include: Input Signal: 4-20 mA DC (300 Ohms internal resistance) Supply Pressure: Maximum of 50 psi Ambient Temperature: -40° to 150°F (-40° to 65°C) Classification: Class I, Groups B, C, and D (hazardous area certified) Product Status & Maintenance Obsolescence: