X-Small (6.5-8.5" around neck, 4.25" neck to snout) fits x-small dogs such as Chihuahuas, cats and kittens), Small (8-10" around neck, 5.75" neck to snout, fits small dogs such as a Maltese or cats),

Medium (12-15" around neck, 8.25" neck to snout, fits small dogs such as Pugs or Beagles),

Large (14-22" around neck, 10.25" neck to snout, Fits medium dogs such as Bulldogs or Boxers) or

X-Large (21-25" around neck, 12" neck to snout, fits large dogs such as Golden Retrievers, Great Danes and German Shepherds).