Size: Asian Size for your reference, the best way to measure size is to measure the widest part across the rib cage of your dog. ☀☀XS: Chest 11.8"-16.5"; Neck 9.8"-13.8"; Length 8.6"; Dog's Weight 3-7 Kg.☀☀S: Chest 16.1"-20.9"; Neck 14.2"-18.5"; Length 10.2"; Dog's Weight 7-9 Kg.☀☀M: Chest 17"-24.8"; Neck 15.7"-18.9"; Length 11.8"; Dog's Weight 9-23 Kg.☀☀L: Chest 19.7"-29.5"; Neck 16.5"-21.3"; Length 13.8"; Dog's Weight 23-30 Kg.☀☀XL: Chest 27.6"-37.4"; Neck 19.7"-28"; Length 17.7"; Dog's Weight 30-40 Kg.Know More About Pet Life Preserver Vest☀☀1. A high quality loop to fasten a leash to while walking the dog.☀☀2. High quality materials, straps and fastening buckle allows for excellent mobility in the water. ☀☀3. Adjustable nylon straps and quick release buckles to get the Jacket off easily.☀☀4. Reflective stripes from side to side to enhance viability you will know where your dog is even at night.☀☀5. Designed for use in swimming, water rescue, rehabilitation, boating and hunting. Safety tips:☀☀Be sure that you have a pet life jacket for your dog or cat and be sure to use the straps to make sure that it fits snugly around your pets chest. Make sure that your pets life vest is not to tight or it could make it harder for your pet to breath.