M39019/03-221 is a two-pole magnetic low-power sealed trip-free circuit breaker designed for defense and aerospace applications per MIL-PRF-39019/3H. This circuit breaker is rated for a current of 2.5 A with time delay Type A, and operates at maximum voltages of 50 V dc and 240 V ac at 60 Hz and 400 Hz. The device features a maximum resistance of 0.25 ohms at dc, 0.25 ohms at 60 Hz, and 0.27 ohms at 400 Hz, with high inrush capability of 800 percent at 60 Hz and dc, and 1,400 percent at 400 Hz. The circuit breaker is sealed and trip-free, providing reliable overcurrent protection in compact military and aerospace systems where space and weight are critical constraints.