ThunderShirt Calming vest for dogs size. XS ≥4–6 kgDoes your pet tolerate vet visits poorly? Will he be derailed by a storm, fireworks or a journey by means of transport? The calming vest from the ThunderShirt brand works similarly to a swaddle for children. It exerts gentle constant pressure on the animal's body, bringing calm and a sense of security. You can also use the vest during training for better results. Or when the dog stays home alone. The XS model is designed for dogs between 4 and 6 kg.