The AP7-1-51-501 is a single-pole, fully sealed magnetic circuit protector designed for reliable overcurrent protection. This model features a series trip configuration with screw terminals, a nominal current rating of 0.500 amperes, and is specified for DC circuits with a short time delay. As a hydraulic-magnetic protector, its trip point is stable over a wide ambient temperature range. The trip-free mechanism ensures the circuit opens during an overload even if the handle is held in the ON position, making it ideal for critical applications such as communication equipment, aircraft instrumentation, and power supplies.