Seresto 81081042 Flea and Tick Collar for Large Dogs. Seresto 81081042, Remains active against fleas and ticks for up to 8 months. Also protects the direct surroundings of the animal against development of flea larvae. Veterinarian Recommended, Non. Most democratic collar of fleas . Greasy, odorless and safe. ticks control. Large Dog 8kg or more