The 4NK0HV is a thermal overload relay from Fuji Electric's "Orange Line" series designed to provide motor overload protection with automatic reset capability. It features a built-in heater for accurate operation, a calibrated rated current dial, manual trip device, and open-phase protection. The relay is equipped with 1NO+1NC alarm contacts and is available in multiple ampere ranges (from 0.1-0.15 A through 12-18 A) to accommodate various motor sizes and contactor frames. The alarm contact is rated for continuous operation at 2.5 A with current-make/break ratings of 15/1.5 A at 110-120V, 7.5/0.75 A at 220-240V, 3.75/0.375 A at 440-480V, and 3.0/0.3 A at 550-600V. This relay is ideal for industrial motor control applications requiring reliable overload protection and is UL and CSA certified.