Walkin' Wheels for Handicapped Pets - Small lets your elderly, disabled, or special needs dog run, play, and get the exercise he or she needs to live a happier, healthier life. Experience the simplicity of Walkin' Wheels for handicapped pets. No more complicated measurements and waiting weeks while carts are built. Walkin' Wheels ships immediately and is adjusted in minutes - no tools needed - with simple snap-locks. Ideal for dogs with rear-end mobility problems including arthritis, hip dysplasia, degenerative myelopathy, disc disease, and more... Small Breed Size Range: Length of dog from back of the front leg to the back of the rear leg 5 to 9 inches. Height of the dog, groin to ground 2 to 5 inches. Width of the dog at the widest point, 2 to 5 inches.