PNOZ s4 24VDC 3 n/o 1 n/c Product ID: 750104 PNOZsigma safety relay (standalone), inputs: 1/2-channel wiring with/without detection of shorts across contacts, manual/automatic start, outputs: 3 N/O, 1 N/C, 1 SC, UB 24 V DC, width: 22.5 mm, plug-in screw terminals, monitoring of E-STOP, safety gates, light guard.