QBLEEV Dog Life Jacket/pool float is designed for dogs of S M L EXTRA LARGE XXL shape and sizes that love to join their humans rafting, kayaking, boating, surfing and paddle boarding. This life preserver also apply for dog who is new swimmer or tired of swimming The chest girth should be the most important and decisive measurement to be considered. SIZE CHAER: S:chest(16-18.9"), neck(11.8-15"), length(9.8") L:chest(21.7-27.6"), neck(15-18.9"), length(13.8") XL:chest:24.4-31.5”neck:16.9-20.8”length:15.7” XXL:chest:28.3-35.4”neck:17.7-22.8”length:17.7” How to Get a Suitable Size for Your Dog? Step 1: Please use a flexible tape to measure the circumference (all the way around) at the widest part of your dog's chest/ribcage; Depending on the breed, it is typically right behind their front legs Step 2: Measure the neck's circumference (the length around their neck) of your dog at the point where his/her collar comfortably sits Step 3: Measure your dog's back length from the base of your dog's neck (where the collar sits) to the base of the tail; When measuring the back length it is very important that your dog is standing in normal position Step 4: Refer to our SIZE CHART to get the right size for your dog,Thanks. NOTE:Please not pulling the tape too tightly when you are measuring. And take any other unique traits (large shoulders, long torso, etc.) into consideration. Explore new ground with life jacket! Our performance gear will keep your pup safely equipped for every new adventure! Do not leave your dog unattended, please supervise while wearing this flotation device.