The vest can be plunged into water and put onto the dog to reduce the risk of overheating. This simple but effective process can be repeated whenever the vest dries out to keep your dog cool, happy, and healthy on hot days. The vest has a belly strap to ensure a snug fit. Size: XS: 25cm, S: 30cm, M: 40cm, L: 50cm, XL: 60cm, XXL: 70cm.