Performance Level (PL): PL e, Safety Integrity Level (SIL): SIL 3, Category: Cat. 4, Operating voltage: 24 V DC ± 20%, via SB4 Housing, Number of channels: 4, Safety output: 2 relay outputs, positively guided normally open contacts, Signal output: Output for displaying the switching state of the OSSDs, Connection: Screw terminals, cable cross-section 0.2 ... 2 mm2 Option /165: Spring-loaded terminals, cable cross-section 0.2 ... 1.5 mm2, Ambient temperature: 0 ... 50 °C (32 ... 122 °F)