Ruffwear Swamp Cooler Dog Vest. The Swamp Cooler Vest is like an air-conditioner for dogs keeping your pup cool and happy while outside! Just soak it in cold water wring it out and fasten around your dog. Using evaporative cooling this vest exchanges the dog's heat with the coolness of stored water. In turn it releases the heat as the water evaporates. Features: - Three-layer construction maximizes cooling effects: - Wicking outer layer reflects heat and facilitations evaporation - Absorbent middle layer stores water for evaporation - Comfy inner layer transfers cooling effect to dog- Light color reflects sunlight and ultraviolet rays for added sun protection- Side-release buckles make it easy to take on/off- Machine washable; wash gentle cycle on cold with buckles secured hang drySizing: XXS: Neck: 13.5 in. | Chest: 13-17 in. | Length: 10.25 in.XS: Neck: 16.25 in. | Chest: 17-22 in. | Length: 12.75 in.S: Neck: 19.75 in. | Chest: 22-27 in. | Length: 18 in.M: Neck: 22 in. | Chest: 27-32 in. | Length: 21 in.L: Neck: 26.5 in. | Chest: 32-36 in. | Length: 23 in.XL: Neck: 28 in. | Chest: 36-42 in. | Length: 24.75 in.If in-between sizes choose the larger coat for more coverage.