Black Flag is a brand of insecticide made by the Clorox company. The make a variety of different products designed for killing insects, including fly spray.
The active ingredients are sumithrin and tetramethrin (Black Flag Flying Insect Killer); propoxur (Black Flag Wasp, Bee & Hornet Killer); ETOC and esfenvalerate (Black Flag Ant & Roach Killer); and permethrin (Black Flag Ant & Roach Killer).
