K9 Advantix II Flea & Tick Spot Treatment for Dogs, over 55 lbs, 1 Dose (1-mo. supply); Help protect your gentle giant from parasitic pests and the potentially harmful diseases they can transmit with K9 Advantix II Flea & Tick Treatment for Extra Large Dogs. This broad-spectrum, veterinarian-recommended treatment is specifically formulated to repel and kill fleas, ticks and mosquitoes on contact with no painful biting required. It further kills all life stages of fleas to prevent re-infestation, and even kills lice while also repelling biting flies. The waterproof formula for puppies and dogs 7 weeks or older and weighing 55 pounds or more continues working for up to four weeks, even after bathing or swimming.