【Small/S Size for 2.3-3.6 kg Dogs】The back length of this small dog chest bag is 23 cm; The chest circumference is approximately less than 40 cm. Note: Be sure to measure your pet before purchasing. Chest circumference: Leave 2.5-5 cm space to ensure your pet is as comfortable as possible. If the size is between two sizes, choose a larger size. 【High Quality】This product is made of breathable mesh and polyester fiber, which is durable and comfortable. Two mesh side panels allow for maximum air circulation. 【Unique Design】Comes with Velcro, zipper and elastic openings that allow you to customize a comfortable fit for your dog. Release buckles at the end of the straps ensure quick one-handed installation. 【Comfortable Experience】With leg-out and tail-out design, it can keep your pet safe and comfortable while keeping your cat or dog close. 【Adjustable Strap】The adjustable straps with clips can be used on the front or back, for easy installation and reducing the burden on your shoulders and keeping your dog or cat close to your heart.