SIPART PS2 smart electropneumatic positioner for pneumatic linear and part-turn actuators; 2-wire; 4...20mA; double action; polycarbonate enclosure Standard Without explosion protection. Connection thread el.: 1/2" NPT / pneu.: 1/4" NPT Without limit monitor. Without option module. . Brief instructions English / German / Chinese. Standard / Fail-Safe - Depressurizing the actuator in case of failure of electrical auxiliary power (single acting only). Without Manometer block / Venting gauge block / Booster