The Ruffwear Singletrak Pack is not only a great day pack for your dog but it is also a water carrier coming with two collapsible water bottles. This pack allows your best friend to carry his/her own water and anything else they need for a great day hike! There are 5 places for adjustments so that this pack can fit your dog perfectly.
 
Sizing measures behind your dog’s front two legs, the girth of their chest:
Small: 22-27 IN
Medium: 27-32 IN
Large/XL: 32-42 IN