Youareking&reg; Christmas Cat Dog Clothes Santa Dog Costumes Pet Apparel XS: Chest girth 11 inches, Back length 9 inches, Neck girth 9 inches S: Chest girth 12.5 inches, Back length 9.5 inches, Neck girth 9.5 inches M: Chest girth 13.5 inches, Back length 10.5 inches, Neck girth 10.5 inches L: Chest girth 16.5 inches, Back length 12 inches, Neck girth 12 inches XL: Chest girth 18.5 inches, Back length 13.5 inches, Neck girth 13.5 inches