The Adams Flea & Tick Collar for Dogs and Puppies is great for dogs and puppies that need ongoing protection from biting fleas, ticks and mosquitoes*. Each collar provides 6 months of protection against adult fleas, ticks and mosquitoes*. Two collars in each tin provide convenient 12 months protection against fleas, ticks and mosquitoes*, keeping your pet and home free of infestations. The active ingredients covering the surface of the collar is rubbed onto the fur of the animal and the solution works its way down through your dog's natural fur and hair oils across the body to protect from head-to-toe. This collar is water resistant and if wet, will not impair the collar's effectiveness or dog's protection from fleas, ticks and mosquitoes*. This collar is also fully adjustable and can fit to size. Simply wrap the collar around your dog's neck (slip 2 fingers flat under the collar to ensure a snug fit, but not too tight), fasten, and snip off the excess length. Once the collar is applied, the active ingredient is transferred from the collar to your dog’s hair, and then to the skin. The collar stays on and in effect even on the most active dogs! (*excluding California)