text: Dwyer 1820-2 Pressure Differential Switch SPDT 10 PSI . Kellan Inc
  Dwyer 1820-2 Pressure Differential Switch SPDT 10 PSI
  This item was purchased from a large business inventory reduction sale. I do not know the history of it. It is in good cosmetic condition. It is also marked, "1820-MIL-2". I am not able to test it. It only comes with what is shown in the pictures.