3-Pack, 23", Lavender Chamomile Fragrance Calming Collar for Dogs Contains pheromone technology, scientifically proven to modify stress-related behavior Works quickly to help modify stress-related behavior, but may not eliminate all unwanted behaviors Works quickly to help modify stress-related behavior, but may not eliminate all unwanted behaviors One collar releases pheromones for up to 30 days, safely and effectively US and International patents pending