Help your dog feel calm, safe and secure with the Adaptil Calm Collar. It releases a synthetic copy of the natural canine appeasing pheromone — the same reassuring signal a mother dog gives her puppies — for drug-free comfort that travels with your dog wherever they go. Because it is worn against the skin, the collar is ideal for on-the-go reassurance: walks, car trips, vet visits, boarding, training classes and busy or unfamiliar places. Wearable, drug-free calming: works continuously while worn, at home and away. Lasts up to four weeks: keep it on continuously and replace monthly for best results. Two sizes: a puppy/small collar fits necks up to roughly 37.5 cm, and a medium/large collar fits necks up to roughly 62.5 cm — trim any excess after fitting. Fit it snugly: position the collar in contact with the skin so the pheromone can work effectively. Prefer whole-of-home coverage? The same appeasing pheromone is also available here as a plug-in home diffuser and a diffuser refill, creating a reassuring environment indoors for settling puppies, easing multi-dog tension and calming nerves during thunderstorms or fireworks.