Sizing: 

X-Small - Length: 7-9" Chest: Up to 14"  Neck: Up to 12"

Small - Length: 11-13" Chest: Up to 18"  Neck: Up to 15" 

Medium - Length: 15-17" Chest: Up to 24"  Neck: Up to 17"

Large - Length: 19-21" Chest: Up to 28"  Neck: Up to 19"  

X-Large - Length: 23-25" Chest: Up to 32"  Neck: Up to 22"