The DMS120 is a Three Phase Voltage Monitoring Relay which protects against Phase Failure (phase loss), Phase Sequence, Phase Asymmetry, Under Voltage, Over Voltage, Neutral Fault and Over & Under Frequency. It can be configured for either 3 wire or 4 wire applications and has adjustable Start (ON) and Trip (OFF) delays. This unit has two seperate 5A relay outputs which can be configured as either Fail Safe or Non-Fail Safe and can be a latched output it required. The DMS110 also has a backlit display which shows current voltage of all three phases and relay status. This is part of the SM800 Series.