QO and QOB one, two and three pole thermal magnetic circuit breakers provide overcurrent protection and switching on ac and dc systems. These circuit breakers have an over center, trip free toggle mechanism with quick make, quick break action and positive handle indication. They also have VisiTrip trip indication, which provides a visual indication that the circuit breaker has tripped and interrupted the circuit. A full line of features and factory installed accessories are also available such as shunt trips, auxiliary switches and alarm switches. This 2 pole QO main breaker is rated at 50A at 120/240VAC. This unit provides 22kA breaking capacity and bolt on mounting. QO circuit breakers are UL Listed under UL File E84967 and are CSA Certified under CSA Master Contract 153555.