Expandable for Extra Space: This innovative pet backpack carrier features a mesh square expandable design. Simply unzip the back to reveal a spacious retractable expansion area, measuring 8.6" L x 13" W x 11" H when fully expanded. This extra space allows your pet to stretch out and relax comfortably during breaks. The breathable mesh design ensures optimal airflow, keeping your pet cool and comfortable throughout the journey. When not in use, the expansion area can be easily collapsed and folded, making it convenient for storage and travel. Transparent Bubble Window & Breathable Design: The transparent bubble window offers your pet a panoramic view of its surroundings, helping to reduce travel anxiety and keep them engaged. You can also easily check on your furry friend at any time. Additionally, this cat bubble backpack is equipped with 10 ventilation holes and mesh panels on the side pockets, side openings, and an expandable back section, ensuring optimal airflow to keep your pet cool and comfortable throughout the journey. The combination of style and functionality makes it the perfect travel companion for your pet.