This collar is designed for dogs and puppies 12 weeks of age or older with a neck size up to 25 inches. It uses a sustained-release system containing deltamethrin, an insecticide that works through combined vapor and powder action to help control fleas and ticks from head to tail. The collar is water-resistant and can be worn during bathing or swimming without impairing its effectiveness. Each collar is designed to control fleas and ticks for up to six months, and the package includes two individually wrapped collars for a full year of coverage. To fit the collar, it is placed around the dog's neck, buckled at the main clasp, and any excess length is fed through the remaining clasps before being trimmed for a clean fit. A properly fitted collar allows two fingers to be placed between the collar and the dog's neck. Maximum effectiveness may take two to three weeks to develop after the collar is first placed on the dog.