TERRO Drain Insect Killer is a powerful solution designed with a dry foam formulation that contains three Insect Growth Regulators (IGRs). Unlike liquid drain products, this unique formulation reduces the chances of missed areas and provides full-contact, 360-degree coverage, making it highly effective in tackling and preventing insect infestations. The IGRs in TERRO Drain Insect Killer disrupt the normal development of immature drain flies, fruit flies, and roaches. Additionally, it disrupts the normal life cycle of drain flies and fruit flies, effectively eliminating them during their pupal stage, thereby breaking the cycle of infestation. To effectively use TERRO Drain Insect Killer, apply the foam into and around the downspout and catch basin to cover the entire area. When treating a double-basin sink, be sure to apply it in both drains. Use the convenient fold-up extension tube for precise application into the pipes. It's important to thoroughly coat these areas, as fly larvae tend to develop in the scum buildup on the sides of drainpipes. The visible foam formulation ensures that no areas are missed during application. This product can be used on all types of pipes. Depending on the severity of the infestation, it's recommended to repeat the application every 2 to 4 weeks.