Thundershirt Heather Grey, Extra Extra Large keeps dogs calm during thunderstorms, fireworks, or helps with separation anxiety, travel, crate training, and more by creating gentle, constant pressure. Pressure has a calming effect on the nervous system and helps relieve anxiety. Thundershirts are a well-designed, inexpensive pressure wrap for dog anxiety. XXL size is for dogs that weigh more than 110 lbs. Please note that this product may only ship via UPS dimensional weight, which is above its actual weight.