AP117-1-72-153 is a fully sealed hydraulic magnetic circuit protector from the Airpax AP series, designed for accurate and reliable circuit protection with inverse time delay and trip-free features. This single-pole unit features screw terminals (-117), series configuration with SPDT auxiliary switch (-1), long time delay for 50/60Hz operation (-72), and a nominal current rating of 15 amperes (-153). The auxiliary switch is rated at 3.0 amps at 120 VAC or 50 VDC, and the unit weighs approximately 1.8 ounces (49 grams) per pole. Unlike thermal circuit protectors, this magnetic circuit protector maintains consistent trip current over a wide temperature range. It is suitable for power switching applications requiring precise overcurrent protection with predictable time-delay characteristics.