Sizing guide: Measure pet’s chest around the broadest part of the chest and
add 2". If the measurement is between sizes or if the pet has a stouter build,
select the next size up for a proper fit.
Sizing Guide
Length
Measure from the base of the tail (where it
connects to the hindquarters) up to where the collar sits at the base
of the neck.
Chest
Measure the entire chest (all the way around) at the widest
point of your pet's chest. This is right behind the front legs.
Neck
Measure the neck (the distance around it) at the point where the collar sits.

X-Small fits girths 7"-16"
Small/Medium fits girths 12"-28"
Large fits girths 28"-36"
X-Large fits girths 32"-44"