The Siemens SIRIUS 3UG4581-2AW31 is an insulation monitoring relay with analog setting. Initial value is 0.85, full-scale value 1.1. It monitors AC voltages from 0 to 400 V at line frequencies of 50 or 60 Hz. The control supply voltage is AC/DC, rated 24 to 240 V at both 50 and 60 Hz — so it works off the same supply it's monitoring, or a separate control voltage in the same range. A single delayed-switching output (1 delayed switching) provides the alarm; there are no NC or NO contacts for delayed switching (0 each), so the output is a single changeover relay with adjustable delay.
Housing is 22.5 mm wide, 78 mm high, 100 mm deep — a standard slimline enclosure that snaps onto 35 mm DIN rail (snap-on fastening). Clearance around the unit is zero in all directions (upwards, downwards, forwards, backwards, at the side), so it can be packed tight against other components without derating for airflow. Mounting position is any orientation. Terminals are spring-loaded (cage clamp) accepting 2x solid conductors 20-16 AWG or 2x stranded 18-16 AWG, and finely stranded with ferrule 0.5-1.5 mm². IP20 protection — suitable for clean, dry control cabinets only.
Brand is SIRIUS, Siemens' industrial control component family.