The Surgi Snuggly comes in 10 basic sizes which are small - x large
and 2 additional sizes which are xxsmall and  xxlarge.

The 10 basic and most common sizes are the following...

Small
Medium
Medium short
Medium long
Large
Large short
Large long
Xlarge
XLarge short
XLarge long

Of these sizes 3 contain short and long versions of the Surgi Snuggly.

The only difference in the sizing is the body length (from the neck to the tail )

Medium short measured from neck to tail is 13"
Medium measured neck to tail is 15"
Medium long measured from neck to tail is 17"

Everything about the 3 medium suits is exactly the same from the weight, to the tail tab legnth, to the tail hole to the leg placement. The only difference in the sizing is the body length (from the neck to the tail )

This is the exact same size model we use for the 3 large and 3 xl sizes too!