FOLDABLE AND EXPANDABLE- The cat backpack straps can expand the back to give your pet more room to move around and reduce their anxiety. Foldable design helps you save space when not in use. BREATHABLE VISIBLE- The cat backpack has 4-7 rip-resistant breathable meshes on the front, top and sides (expandable or not when not expandable) to give you more ventilation and make it easier for you to see your pets inside. The top of the dog backpack can be Open and let your cat/dog stick its head out. LARGER THAN ANY OTHER SIZE- Expanded: 21.7" x 13 x 15", Unexpanded: 13" x 9.8" x 15". Suitable for pets under 15 lbs, such as most cats, puppies, rabbits. TRAVEL FRIENDLY- Portable pet backpack with breathable back panel, padded adjustable shoulder straps and chest buckle for travel, hiking, walking and outdoor activities, a real cat travel backpack. QUALITY AND FUNCTIONALITY- This expandable cat backpack is made of high quality polyester and scratch resistant mesh, which is sturdy and safe for your pet. 2 side pockets for pet supplies and a built-in safety leash to prevent pets from escaping.