Like new Thundershirt in size XS for dogs 8-14 lbs. I couldn’t get my dog to wear it so it has only been tried on, but has been washed. Fabric is a soft knit rayon/polyester/spandex blend with Velcro. Box & fitting instructions included. ThunderShirt is the original, vet recommended, natural calming solution that helps reduce anxiety in dogs in a drug-free way. The vest's patented design applies gentle, constant pressure to calm all types of anxiety, fear, & over-excitement issues in dogs.