Really worked last year. 2 dogs 2 cats on open pasture to loafer means bad flea and a few ticks non stop. Drops on neck worked 2 weeks if lucky. The dog dose and cat ingredents are the same and same amount. So I get 2 large and cut in 1/2 used on dog and 1 cat. The other 2 cats get 1/2 each. I had given up hope on stopping fleas former Chihuahua breeder and past shower. I had gone through any medicine made for fleas. Nothing worked till Adnantage by Bayer. It worked 5 years till fleas mutated. Seresto is same maker. And it kicked flea rear. My cats go through our pasture and 2 others with woods near hunting mice. 2  are Huge Main Coon nutered. The other a 1/2 MC and persian so slower and more lazy So no suprise birds. Just a few mice a week. And THANK YOU BAYER no fleas.