【Expandable for More Space】Expanded size: 13.8"L x 9.3"W x 14.2"H. This cat carrier with an expandable back design provides additional space and enhanced air circulation, allowing your pet a more comfortable and relaxed environment and reducing anxiety. The real ever bigger expandable cat backpack. 【Dimensions of Cat Backpack Carrier】The large cat carrier backpacks measure 12.6" L x 11.4" W x 16.5" H, recommended for pets within 12"L x 10.8"W x 14.5"H. It is designed to accommodate cats, dogs, puppies, and most small-to-medium sized pets comfortably. It is sufficiently spacious to accommodate two cats. For a precise fit, please measure the length and height of your pet in a sitting position. 【Superior Ventilation and Visibility】This cat backpacks for carrying cats features breathable mesh windows on three sides, allowing for ample airflow and easy observation of your pet as they enjoy the surrounding scenery. The expanded back panel to be a giant tent bed for your furry friends to enjoy outdoor time with nature and sunshine well without feeling stuffiness in the cat bag, the best ventilation ever.