ENTES MK-01 Phase Failure Relay, also known as a Motor Protection Relay.
Key features:
Designed to protect three-phase motors from overheating and damage caused by phase faults and voltage unbalance (asymmetry).
Monitors phase loss and phase sequence, and can be configured for adjustable asymmetry.
Features a relay output (typically 1 C/O contact) and indicators for "Out" and "On" status.
Mounts on a DIN rail and is suitable for industrial applications.