Harris Black Label Bed Bug Killer Kills Resistant Bed Bugs & Their Eggs - Kills even the toughest "pyrethroid resistant" bed bugs and eggs that have built up a resistance to traditional pesticide. Quick kill knocks down bed bugs fast when sprayed directly and long residual continues to kill bed bugs for up to 16 weeks after initial application. Odorless and non-staining formula will not cause damage to fabrics when used according to label directionsThere are small pockets of pyrethroid resistant strains of bed bugs in located in some cities in the US. For those strains, tough pyrethroid resistant insecticides are needed to effectively eliminate the bed bug colony. We recommend using this product in combination with our bed bug aerosol and diatomaceous earth powder.