✔️【Expandable Design】 -IDEE Expandable cat carrier backpacks offer more space for pets to move around, reducing their anxiety during the trip. Dimension of cat travel bag: 14.57’’L*10.24’’W*15.75". Extension dimension: 23.62"L x 10.24"W x 15.75"H. This cat carriers for medium cats under 20lb. It can be lay down to use as cat carrier airline approved under seat. ✔️【Ergonomic Design】 - Expandable Pet carrier backpack with extra thicker and breathable pad on adjustable and widened shoulder strap and back to increases comfort and reducing loading pressure. Chest and belly straps of the cat carriers can prevent shoulder strap deviation and maintain the stability, well distributing the weight and balance loading for long walking, hiking and other outdoor activities. Lenghthening handle design is easy to fix to luggage and car safety belt. ✔️【 Ventilation & Visibility】 -This dog hiking backpack has side and top entrances which make your pet easy to stick their head out out. You can feed or play with them without putting the dog travel bag down. And the surrounded breathable mesh windows for visibility and air ventilation. The front and side large mesh windows lets more light in. Pets can have a good view of the surroundings and breath freely during journey, feeling relaxed and peaceful.