ZenDog-Calming Compression Shirt: Medium. The calming compression shirt is a drug-free way to calm and soothe anxious pets. It applies gentle, maintained pressure. Use for decreasing anxiety created by crating, separation, noise, travel and other stressors. It can also calm pets that tend to bark or vocalize excessively. The lightweight, breathable fabric won’t overheat pet and can act as a cooling garment when wet. Adjustable custom fit in several sizes. Imported.