This collar offers continual release of the same natural appeasing pheromone emmited by mothers to reassure their puppies. Dogs recognize these pheromones throughout life and they have a relaxing effect on both the young and adults. Activated by the dog's body heat, the D.A.P. collar releases pheromone over 4 weeks making it an ideal way for owners to help control stress related behavior, as well as letting their pet socialize with other dogs.The puppy/small dog collar fits necks up to 15". Studies showed puppies that wore the collar showed improvement in learning and a reduction in fear and anxiety levels. The collar also helped dogs cope with new situations such as adjusting to new pets, visitors and strange environments, as well as thunderstorms and fireworks.