Square D Miniature Circuit Breaker, Amps 40 A, Circuit Breaker Type Standard, Number of Poles 2

These QO series miniature circuit breakers plug into place in NQOD and NQ panelboards and QO load centers without requiring DIN rail or bolts, so they're easier to install than bolt-on and unit-mount breakers. They interrupt currents when low-level faults are detected in the circuit. They connect to the power supply through bus bars, which eliminates the need to pigtail wires and helps organize the panelboard or load center.