I just ordered the xsmall thundershirt for Chase. Since he's pretty much in between sizes, I emailed them (2 times, but only heard back from the 2nd one).
Here is what I sent them
Message:
I have a sizing question. My dog is about 17" around (give or take an inch) and is about 14 lbs. Not sure if I should get the small or xsmall? Please let me know.
Thank you,
Their response
We do suggest going with the smaller of the two sizes if stuck in between.
Thank you!
www.thundershirt.com
732 Washington Street
Durham, NC 27701
service@thundershirt.com
Toll Free: 866-892-2078