The Airpax™ AP series are fully sealed, magnetic circuit protectors that combine power switching and accurate, reliable circuit protection with inverse time delays and trip free features.
Unlike a thermal circuit protector, the AP does not change its trip current over a wide temperature span. In addition, the AP magnetic circuit protector is available in either DC, 50/60Hz or 400Hz versions and with various delays to match the protector to specific application requirements.

M39019 series is a hermetically sealed circuit breaker, comparable to the standard AP/UP series.
Smaller than M55629. Current ratings 0.05A-20A, up to 240Vac/50Vdc.
More commonly used than M55629.
• Higher shock and vibration options available. These parts will start with AP and will contain 87054, 87055, 87056, 87057, or 87059. E.g., AP1-R-87055-043.
• Refer to the MIL-PRF-39019 specification for specific part attributes, test requirements, and other details