Royal Pooch Sizing For best fit, use measurement B and measure your dog from the base of the neck to the base of tail. XX-Small A -9”, B -8”, C -12” Fits most Chihuahua, Shih Tzu, Yorkshire Terrier, and similar size dogs. X-Small A -9”, B -9.5”, C -14” Fits most Bichone Frise, Brussales Griffon, Maltese, Miniature Pinscher, Papillon, Tea Cup Poodle, and similar size dogs. Small A -10”, B -11”, C 16” Fits most Miniature Dachshund, Norfolk Terrier, Pekingese, Toy Poodle, and similar size dogs. Medium A -11”, B -13”, C -18” Basenji, Pekingese, Pomeranian, Silky Terrier, and similar size dogs. Large A -13”, B -16”, C -22” Beagle, Dachshund, Jack Russel Terrier, Lhasa-Apso, Pug, Miniature Schnauzer, Scottie and similar size dogs. X-Large A -17”, B -19”, C -28” Australian Terrier, Border Collie, Cocker Spaniel, Corgi, Schnauzer, West Highland Terrier, and similar size dogs.