QO single-pole tandem circuit breaker. Ideal for overload and short-circuit protection of electrical systems. Offers 2 circuits in the space of 1. Compatible with QO load centers, CSED devices, and NQOD panel boards. Equipped with the exclusive Visi-Trip indicator. Only to be used in load centers built prior to 1967. When breaker is tripped, the handle snaps to a midpoint position and a highly visible, red indicator easily identifies the tripped breaker. ANSI (American National Standards Institute) certified and UL (Underwriter's Laboratories) listed is rated for 120 volt/240 volt and 10,000 AIR. For use in load centers manufactured prior to 1967 and in modern QO Plug on Neutral style load centers.