The 4120 thermal circuit breaker has UL 1077 approval. It is a high-performance, single pole breaker that includes a trip-free mechanism and push/pull, on/off manual actuation (M-type TO CBE to EN 60934). The 4120 circuit breaker is designed for 115 VAC (400 Hz) or 28 VDC applications from 1 to 25 A (0.5 A available). It is qualified to operate in ambient temperatures up to 125°C with typical life of 20,000 mechanical cycles and 5,000 inductive cycles, ensuring continuous service. Optional polarized or unpolarized auxiliary contacts provide additional signaling up to 0.5 A at 28 VDC. Other options and accessories include thread neck size selection, terminal hardware, identification collars, and lock out rings.