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 various versions (DC, 50/60Hz, or 400Hz) with adjustable delays, these protectors are suitable for diverse application requirements. A key feature is the 'trip-free' action, ensuring the circuit opens even when the handle is held in the ON position. The AP series is also known for its waterproof panel integrity, achieved through an O-ring bushing seal and silicon rubber gland. The UP series, with UL and CSA certification, is approved for operation at various voltages and currents, and the AP-MIL protectors meet MIL-PRF-39019 standards. Typical applications include communication, navigation, aircraft instrumentation, radar, and power supplies.