Dog Pet Puppy Boat Saver Life Jacket Vest Reflective Strip YELLOW (Fits Chest 12" - 16" Length 6") size XS PLEASE MEASURE YOUR PET and compare to the chart provided as each brand and style of pet clothing has its own sizing system. One brand size M can very well be another brand size XL! Each listing has its own unique chart and no two listing charts are the same. Size XSmall: Fits Chest 12" - 16" Length 8"