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. This QO miniature breaker is rated as 40 A, 120/240 V, and 3 pole. This unit provides 10 kA breaking capacity and plug in mounting. A full line of factory installed accessories is also available such as shunt trips, auxiliary switches and alarm switches. QO breakers use a compact 3/4 inch width design for small system footprint. QO circuit breakers are UL Listed under UL File E84967 and are CSA Certified under CSA Master Contract 153555