The Airpax AP series are fully sealed, magnetic circuit protectors designed to combine power switching with accurate and reliable circuit protection. Unlike thermal protectors, the AP maintains a consistent trip current across a wide temperature range. Available in DC, 50/60Hz, or 400Hz versions with various delays, the AP series is suitable for diverse applications including communication, navigation, aircraft instrumentation, radar, and power supplies. A key feature is the “trip-free” action, which ensures the circuit opens even if the handle is held in the ON position. The AP series is also available as the UP series, recognized by UL and CSA, and the AP-MIL series, produced to MIL-PRF-39019 standards.