Practicable Reference Size of Small: L 2.36" x W 2.17". Lonsuneer waterproof dog boots are reliable paw protectors for dogs, flexible, lightweight, sturdy and hand washable, capable to protect paws indoors and outdoors. Please measure across the whole paw pad to get the measure of paw width and length. These boots are relatively flexible and roomy, so a snug fit is better. If your dog's paws are in between 2 sizes and if you've chosen the larger one, you could kindly try to use socks for dog inside the boots and then the boots may stay on better. Kindly Attention: Though the soles are waterproof, the boots can not be applied in deep water, because there may be water seepage through sewing needle holes.