The Classic ThunderShirt Anxiety Jacket for Dogs is the original natural calming solution. Like swaddling an infant, it has a patented design that applies gentle, constant pressure to calm all types of anxiety, fear and over-excitement issues. The Thunder vest for dogs is well-suited for use during thunderstorms, fireworks, separation anxiety, travel, vet visits, problem barking, reactivity and other stressful situations. It's backed by science and is easy to secure to your pet. The ThunderShirt Anxiety Jacket for Dogs is available in sizes ranging from XXS up to XXL.