Find the right treatment for your dog K9 Advantix II is for use on all breeds of dogs ages 7 weeks and older, weighing more than 4 pounds. Use your dog's weight to determine which size is right for them. If your dog is on the cusp, choose the size that accommodates your dog’s current weight. If you have a growing puppy that may exceed the product's weight guidelines within a couple of months, consider purchasing a smaller pack count. How to apply: Apply entire contents of tube along top of dog’s back, between shoulders down to the base of the tail in even spots. At each spot, part hair until skin is visible. Number of spots for size and weight of dog: Small & medium dogs get 2-3 spots, Large & x-large dogs get 4-6 spots. Waterproof after 24 hours: When can I bathe my dog after application? Your dog is free to be bathed or swim after K9 Advantix II has been on for 24 hours. We recommend bathing your dog before applying K9 Advantix II. Your dog needs to be dry at the time of application. If you bathe your dog between treatments, use a general grooming shampoo for pets.