M39019/02-258 is a magnetic, low-power, sealed, trip-free one-pole circuit breaker with auxiliary contacts, designed to meet MIL-PRF-39019 military performance specifications. It features a current rating of 20.0 A with time delay B, and operates at voltage ratings up to 50 V DC and 240 V AC at 60 Hz and 400 Hz. The circuit breaker has a maximum resistance/impedance of 0.006 ohms at DC and 60 Hz, and 0.007 ohms at 400 Hz, with high inrush capability of 800% at 60 Hz and DC, and 1,400% at 400 Hz. The unit weighs approximately 50 grams and includes O-ring sealing with a .375-32 UNEF-2A threaded bushing for panel mounting. This circuit breaker is suitable for military and aerospace applications requiring reliable overcurrent protection with auxiliary contact functionality.