We have a large, black, double coated dog who heats up easily under direct sunlight or warmer temperatures. Wearing this vest, our dog noticeably looks more comfortable and feels cool to touch -- neighbourhood walks, forest hikes, even travelling in the car.
To "supercharge" the vest, we soak it in ice water before putting on our dog.. When it feels dry again, we simply pour another bottle of water over it.
Before getting the vest, our dog would pant more or simply want to lie down in the shade. With the vest, our dog just focuses on having a good time. Very happy with it. Worth every penny.
P.s.: Our dog has a long torso. We wanted the vest to cover her whole backside. So we had to order a couple sizes up for better bum coverage (which means we did bit of handstitching to get it to fit 'round her chest/neck. it worked).