The collar is worn around a dog's neck and continuously releases a synthetic version of the pheromone a mother dog produces to calm and reassure her puppies. Because the pheromone travels with the dog rather than staying in one room, it offers a portable alternative to plug-in diffusers or sprays. Each collar is designed to remain effective for about 30 days of wear. Fitting requires trimming the collar to the correct length after allowing extra room for movement and, in growing dogs, for future growth. A newly stretched collar may show a visible powder that carries the pheromone and is not intended to cause harm. The product is not classified as a pharmaceutical and does not require a prescription. Owners are advised to periodically recheck the fit, especially on puppies.