SIPART PS2 smart electropneumatic positioner for pneumatic linear and part-turn actuators; 2-wire; 4...20mA; double action; polycarbonate enclosure . Without explosion protection Connection thread el.: 1/2" NPT / pneu.: 1/4" NPT Without Without . Brief instructions German / English / Chinese Standard / Fail-Safe - Depressurizing the actuator in case of failure of electrical auxiliary power without mounted pressure gauge block