"SQUARE D QO" DOUBLE POLE CIRCUIT BREAKER 240V 50A Double Pole Circuit Breaker Non-interchangeable 10,000 AIR Visi-Trip Indicator Plug-on Design, Easy To Install Trips Thermally (In An Overload Situation) Or Magnetically (Under A Short Circuit Situation) Quick Make - Quick Break Mechanism Fits Q.O. Panels Standard Ove