Your dog will appreciate the cooling effect of the Ruffwear Swamp Cooler Dog Vest during hot hikes. Just soak this vest with water secure around your dog and as the water evaporates away from the three-layer material the cooling effect of the evaporation will help your pooch beat the heat. And for dogs with dark-colored fur the light color of the Swamp Cooler will be particularly helpful when the sun is beating down.