Thundershirt Dog Anxiety Polo Shirt, Major League Baseball Officially Licensed The patented ThunderShirt design applies gentle, constant pressure to calm anxiety, fear, and over excitement. Calms during fireworks, thunder, separation, travel, vet visits, and much more with no training and no medication so your dog stays drug-free. Great for rescue dogs. Already over 80% successful at helping millions of dogs. Recommended by thousands of vets and trainers. Also works with ThunderLeash. Money-back guarantee: We stand behind ThunderShirt. If you are not satisfied for any reason, simply return for a refund of your purchase price. Backed by science: Dr. Temple Grandin and other leading behavior scientists studied ThunderShirt and found it effectively calms dogs.