M39019/01-250S is a one-pole magnetic low-power sealed trip-free circuit breaker designed for aerospace and military applications per MIL-PRF-39019/1H. This circuit breaker is rated for a current of 10.0 amperes with standard delay time characteristics and operates at a maximum voltage of 50 V dc or 240 V ac at 60 Hz and 400 Hz. The device features a maximum DC resistance of 0.018 ohms and impedance of 0.021 ohms at 60 Hz and 0.024 ohms at 400 Hz, with maximum wattage losses not exceeding 3.0 watts. The circuit breaker incorporates screw terminals with an insulating block (Configuration 2), panel-mount design with a 0.610 inch diameter maximum main terminal, and is sealed to protect against environmental contamination. It is commonly used in aircraft electrical systems, avionics, and other mission-critical applications where reliable overcurrent protection and trip-free operation are essential.