【Expandability】Provides extra space for your pet with its expandable back, creating a cozy zone that increases airflow and more comfortable movement. 【Ventilation and light】 - 1. The top of this backpack can be opened, let your pet’s head stick out, open the mesh zipper for breathability and visibility, and put on sunscreen to prevent sunlight. -2. The design of the three-sided acrylic plate allows good light transmission, to ensure air circulation and avoid excessive heat. 【Adjustable shoulder strap】Wide design, adjustable shoulder pad to help reduce the load and improve the comfort, there are two retractable buckles at the top and bottom to prevent the shoulder strap from deviating, thus maintaining the stability of the backpack. 【Summer and winter use】Solid bottom detachable, compressible, can be used on both sides: the bottom mat is made of flannel. In winter, pets can stay indoors to stay warm and comfortable; the other side is Oxford designed for summer, cool and breathable! It