Help your dog beat the heat with this innovative cooling vest. Just soak it in cold water, wring it out, and fasten around your dog. Evaporative cooling (like an actual swamp cooler) exchanges the dog's heat with the coolness of the stored water in the vest to keep them comfortable and ready to run that extra mile. Measure dog at deepest part of the chest. USA.Dog cooling vest in sizes: S( 23"-30"), M(27"-32").