Small- Length- 12-16" Girth- 12-16" Neck - 6-10" Medium- Length- 16-20"-Girth- 16-19"-Neck - 10-14" Large- Length- 20-26"-Girth- 19-26"- Neck 14-16" X-Large- Length- 26-30"- Grith-26-32"- Neck-18-20"