120 Amp Auto Reset Hi-Amp Circuit Breaker (1 Per Quantity) Commonly referred to as type 1 circuit breakers. Typically used in primary feeder circuits in trucks buses RVs and marine applications; also used in battery chargers and welding equipment. The internal composite alloy material will deflect and separate the contacts when an over-current situation occurs and return to the run mode as it cools. The auto reset circuit breakers operation will continue to recycle until the source of the overcurrent is removed or corrected.