This brand-new, never worn ThunderShirt is a size Large, for dogs 41-64 lbs. ThunderShirt is vet recommended to help calm your dog in stressful situations. ThunderShirt applies a gentle, constant pressure to your dog’s torso, like swaddling an infant or a comforting hug to help them feel calmer. ThunderShirt is safe, easy to use and made from soft stretchy material. For many dogs, thunderstorms and fireworks can be terrifying experiences. ThunderShirt can reduce panting, drooling, shaking and other signs of anxiety. Using ThunderShirt while traveling can make it a more comfortable ride for you and your dog.