Vectra 3D Purple for Dogs 56-95 lbs - 3 Doses Can be used on Dogs and puppies 8 weeks of age and older. Fast acting. Reduced flea feeding in 5 minutes. kills fleas in 6 hours. Kills on contact. Parasites do not have to bite to die. Broad spectrum protection. Monthly dose repels and kills fleas, ticks, mosquitoes, biting and sand flies, lice and mites (excluding mange mites). Long Lasting, quick drying, convenient topical treatment with patented applicator. Remains effective after bathing or swimming. Each monthly dose controls development of all flea stages; Prevents, controls and stops flea infestation and prevents re-infestation.