(Sergeant's) Refill unit for the Sentry Calming Diffuser. Releases Good Behavior pheromones into your home to provide dogs with calming sensations. Pheromone technology has been proven to modify stress-related bad behavior. Ideal for chronic stressful situations such as separation anxiety, thunderstorms, fireworks, or the addition of a new pet. Refill unit for the Sentry Calming Diffuser lasts up to 30 days. Lavender chamomile fragrance.