Spare your cat and yourself the pesky presence of fleas with Advantage II Flea Control for Cats. Advantage flea control with imidacloprid kills 98% of fleas within 12 hours and continues to work for at least a month. Advantage II flea control for large cats is formulated for cats over 9 lbs. Advantage II flea treatment can be used on kittens over 8 weeks old and is safe for cats that are pregnant or nursing. Apply water-resistant Advantage flea treatment once a month between your cat's shoulder blades.