The Airpax AP series magnetic circuit protectors combine power switching and accurate, reliable circuit protection with inverse time delays and trip-free features. Unlike thermal protectors, the AP maintains a consistent trip current across a wide temperature range. Available in DC, 50/60Hz, or 400Hz versions, these protectors are suitable for communication, navigation, aircraft instrumentation, radar, and power supplies. The 'trip-free' action ensures the circuit won't remain closed during an overload, even with the handle 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.