Size Measurements  Fit
X-Small  Girth 12-18" x Neck 11" Fits Dogs 7-12 lbs
Small  Girth 14-22" x Neck 13" Fits Dogs 12-18 lbs
Medium  Girth 18-28" x Neck 15.5" Fits Dogs 18-26 lbs
Large  Girth 22-34" x Neck 18" Fits Dogs 26-35 lbs