565 Plus XLO combines the power of natural pyrethrins with two powerful synergists in a pressurized insecticide. Pyrethrins are derived from the Chrysanthemum flower and have a quick action that attacks an insect’s central nervous system. Pyrethrins also act as irritants to insects, making it an effective flushing agent, and as a repellent to keep insects away. The complexity of pyrethrins means insect resistance is not a concern. 565 Plus XLO also contains piperonyl butoxide and MGK-264, two synergists that help to stabilize and boost the power of the natural pyrethrins.