Sizing: 

X-Small - Girth: 12-15" Length: 9" Weight: 5-9 lbs

Small - Girth: 14-17" Length: 11Weight: 8-13 lbs

Medium - Girth: 17-21" Length: 14" Weight: 12-19 lbs

Large - Girth: 20-24" Length: 16" Weight: 18-28 lbs

X-Large - Girth: 23-27" Length: 19" Weight: 26-40 lbs