The Sentry Calming Collar for Dogs helps dogs in fearful or stressful situations. It goes where your dog goes whether it's at home or on the go! How does it work? Sentry Calming Collar for Dogs mimics the pheromone that the mother dog produces to calm and reassure her puppies. Dogs recognize these pheromones throughout life. It mimics the natural way to help dogs cope with new and fearful situations. The lavender and chamomile provide a soothing fragrance.