Sergeants Gold Squeeze-On for Cats & Kittens 5 lbs.and over is formulated with a revolutionary new adulticide called Etofenprox. Etofenprox has a very low toxicity profile yet it is four times more effective at killing fleas than the other leading OTC brand. Etofenprox when applied monthly kills adult fleas ticks & repels mosquitoes including the mosquito that carries West Nile virus for up to one month. Also includes nylar an insect growth regulator that kills flea egg and larvae for up to three months per application. Five Way StrongÉ.Gentle All Month Long!