IUGNF66-39709-439 is a hydraulic magnetic circuit protector from the IAG/IUG/IEG/CEG/LEG series manufactured by Airpax, designed to provide low-cost power switching, reliable circuit protection, and accurate circuit control for equipment in the international marketplace. This delay code 66 variant features an inrush pulse tolerance of approximately 25 times rated current, enabling it to withstand temporary overcurrent conditions without nuisance tripping. The device exhibits variable trip time characteristics across different current levels, ranging from 50 to 700 seconds at 125% of rated current down to 0.014 to 3 seconds at 1000% of rated current, providing flexible protection across a wide range of fault scenarios. The protector is suitable for applications requiring supplementary circuit protection in industrial and commercial equipment where compliance with international standards and reliable fault isolation are essential.