Size & Material: Medium size --- chest(22.0-27.2in), neck(13.0-20.5in), capacity 9L; Large size- chest(27.2-31.9in), neck(15.7-22.4in), capacity 12L. It is made of high quality nylon fabric material Breathable & Reflective --- Cooling mesh provides airflow and keeps your dog feel comfortable when wear it. The bright color and reflective of dog harness backpack ensure the safety in dark Adjustable Straps & Back Handle --- You can adjust the harness backpack to a proper fit and keep the pack in place. Soft handle can control your dog easily and help your dog Cross obstacles in uneasy situation Removable Saddle Bag & Durable D-ring: The saddle bag is disassemble, your dog can just wear harness if necessary. The D-ring in back is used to connect dog leash, you can hang ID tags and some other small things on the front D-ring High Capacity Pockets & Buckle Design: The saddle bag has 4 pocket, it can store all your dog's travel essentials and your personal belongings. Sturdy buckles make it easy to put on and take off. It is perfect for dogs’ daily walking, hiking, camping or training