X-Small: 7.5” L x 6.5” W / 8.75” neck circumference / fits up to 6 lbs
Small: 10.5” L x 7.75” W / 11.25” neck circumference / fits 7-11 lbs
Medium: 12” L x 9.25” W / 14” neck circumference / fits 12-19 lbs
Large: 15” L x 10.75” W / 16.5” neck circumference / fits 20-30 lbs