Each PetArmor Flea & Tick Collar for Dogs kills fleas and ticks for six months when worn continuously. This vet-quality flea and tick collar is safe for pups 12 weeks old and up and is a one-size-fits-all. A PetArmor Plus flea collar kills adult fleas, flea eggs, and flea larvae helping to prevent reinfestation. Flea and tick prevention for dogs protects your furry family member from ticks that may transmit Lyme disease. Flea and tick treatment includes two waterproof collars for a whole year of all-weather, whole-body protection. | PetArmor Plus Flea & Tick Collar for Dogs, Pack of 2, Grey