The preferred successor is 3UG56421CW30 digital monitoring relay voltage monitoring, 22.5 mm from 10 to 600 V AC/DC overshoot and undershoot 24 to 240 V AC/DC 50 to 60 Hz DC and AC noise pulses delay 0.1 to 20 s hysteresis 0.1 to 300 V 1 changeover contact with or without fault buffer screw terminal.