Spare your dog and yourself the pesky presence of fleas with Advantage II Flea Control for Dogs. Advantage flea control with imidacloprid kills 98% of fleas within 12 hours and continues to work for at least a month. Advantage II for medium dogs is formulated for dogs 11-20 lbs. Advantage II flea treatment can be used on puppies over 7 weeks old and is safe for dogs that are pregnant or nursing. Advantage flea control is water-resistant and protects your dog through baths, rain or swims. Apply Advantage once a month between your dog's shoulder blades with an easy squeeze tube.