Johnson's 4fleas Spot-on for Cats over 4kg is a fast-acting spot-on that kills fleas on contact on your cat and surrounding area. This treatment provides up to 2 months protection and contains 2 vials, each vial giving up to 4 weeks protection. Kills fleas and biting lice as well as killing flea larvae in the area around your cat. Veterinary approved active ingredient: Imidaclopramide. Each pack contains 2 pipettes, each of which prevent further reinfestation for 4 weeks, providing a total of 8 weeks prevention. Fleas are killed within one day following treatment.