Zero In Flea Killer Comb. Zero In Flea Killer Comb delivers a targeted electrical charge to the coat of cats or dogs, killing fleas on contact. The comb is simple to use and provides effective and chemical-free control of parasitic insect pests. Safe and effective - destroys fleas instantly.Safe and effective flea and tick control for use on cats and dogs.Delivers electrical charge harmless to pets.Kills and removes adult fleas, larvae and eggs.Ergonomic design with push-button control.