PetTa Grey Cute Argyle Design Christmas Doggie Sweater S SIZE S is for dogs whose back length is 11.8 inches.Back length here is the size from the base neck to the base of the tail. Classic argyle design makes your dog always fashionable. Acrylic fibers material makes your furry friends warm in cold days, and you can easily take care of the sweater. Machine washable with similar color, tumble dry. Fit for small and medium dogs. But please choose the right sizes according to the size chart above.