Rating for this circuit breaker at 120 voltsAC
2 amps.

Voltage ratings for switches and breakers are specified as the maximum the device can operate safely at without causing arc fault or breaking down.

DC and AC are different in that the make/break operation is different: in short, because AC crosses zero-voltage, the switch or breaker can do so with less arc.

So, in summary, you can use this breaker and expect it to trip at 2 amps, but don't exceed its 250 volt AC rating.