The SE Relays 831 series voltage sensor is designed to be wired across terminals A1 and A2 with the voltage being monitored, capable of detecting overvoltage and undervoltage conditions through the Umax and Umin dials, which set the upper and lower trip-points respectively. The relay has SPDT silver alloy contacts rated at 15A at 12VAC, allowing for a 10-second delay before transferring the contacts as specified on the timing dial, with three-state indication LEDs indicating normal or faulty states via different colors of red or green LED lights.