Like swaddling an infant, Mellow Shirt uses gentle pressure to calm all sorts of fear and anxiety problems | Use for thunder, fireworks, vet visits, car travel, crating, problem barking and much more | Made with lightweight, breathable, machine-washable fabric, drug free and comfortable for your dog | Very easy to put on and take off, hook-and-loop fasteners make adjusting for gentle pressure a snap for most any size dog | Size Small fits most dogs 15 to 25 pounds and with a chest circumference of 17 to 21 inches, please measure dog before ordering