AP1-1090-1 is a single-pole hydraulic magnetic circuit protector from the Airpax AP series, designed to combine power switching with accurate and reliable circuit protection. This fully sealed protector features inverse time delays and trip-free operation, ensuring the circuit opens on overload even when the handle is forcibly held in the ON position. Unlike thermal circuit protectors, the AP series maintains consistent trip current over a wide temperature span from -40°C to +100°C. The unit offers dielectric strength of 1250V RMS at 60Hz, insulation resistance exceeding 100 megohms, and withstands 100G shock without tripping while carrying full rated current. Typical applications include communication, navigation, aircraft instrumentation, radar, and power supplies where reliable circuit protection is essential.