The MAG03D0424 is a Phase Failure Relay which can be use for both a 3 or 4 wire application, switchable by a dip switch. The Supply voltage can also be selected between 208-480Vac 3 wire and 120-277Vac 4 wire. It has Phase loss, Reversal and Asymmetry as well as adjustable under and over voltage set points. The ON/OFF time delays are also adjustable. All of this in a compact 17.5mm housing.