This relays has a self-control over its own supply of voltage. It has LED status signals and a real RMS measurement. Its H3US and M3US relays manages 3 phase networks including overvoltage in between phases and undervoltage between phases. On the other hand, the H3USN relay has the ability to have control over another 3 phase networks including overvoltage between phases nad neutral as well as undervoltage between phases and neutral and the neutral loss. It is also a multi-voltage equipment.