Advantage II Cats: 4-Month Supply This formula with IGR kills all life stages of fleas, and contains Imidacloprid, which acts to disable a flea's nervous system. It provides once-a-month topical flea prevention and treatment for cats, 8 weeks and older. Features: Kills all flea life stages, preventing fleas on treated pets from infesting your home Kills adult fleas already on a pet within 12 hours and re-infesting fleas within 2 hours Waterproof Fast and easy dermal application Only one application a month necessary Safe on cats 8 weeks and older Item Specifications: Weight: 5-9 lb. (Orange) Over 9 lb. (Purple) Application: Apply entire contents of tube on the neck at the base of the skull. Monthly application. Length of Effectiveness: Under normal conditions, the product is effective for a month. However, in cases of severe flea infestation, retreatment may be necessary earlier than four weeks. Do not retreat more often than once every seven days. After flea control is attained, return to a monthly retreatment schedule. Active Ingredients: 9.1% Imidacloprid 0.46% Pyripoxyfen 90.44% other ingredients 5/9lb 5420208 405584 724089202086