Gentrol Point Source is a special Roach control device that contains the Gentrol Insect Growth Regulator (IGR) hydroprene for 90-day control of roaches and other stored product pests. Activating Gentrol Point Source is as simple as squeezing the raised end of the plastic, adhesive-back device. This releases Gentrol IGR onto a filter paper. From there, it moves up to 75 square feet, damaging adult roaches and preventing them from reproducing. 20 units per box.