High Quality Material: The pet backpack is made of polyester, which is lightweight and durable. The breathable mesh material on both sides of the dog backpack has good air permeability, which ensures air circulation inside the backpack and makes the pet more comfortable. The unique design of the pet backpack allows your dog to stretch both front legs and place it over your shoulder or back. Size: S: bust 60-66cm, back length 43cm, neck circumference 30-40cm, suitable for pets weighing 0-5kg. M: bust 70-76cm, back length 50cm, neck circumference 35-45cm, suitable for pets weighing 4-9kg. L: bust 75-80cm, back length 58cm, neck circumference 40-50cm, suitable for pets weighing 8-18kg. XL: bust 83-94cm, back length 68cm, neck circumference 48-63cm, suitable for pets weighing 16-30kg. Large capacity storage: the three pockets of the dog backpack can store snacks, garbage bags and toys. The stylish dog backpack is perfect for travelling, camping, hiking or taking your pet to the vet. The thickened and widened shoulder strap design of the dog backpack is ergonomic, providing you and your pet with a comfortable experience. Safety and comfort: The thickened bottom design of the pet backpack can better protect the pet's safety. The adjustable collar can be adjusted according to the circumference of the dog's neck, which makes the pet more comfortable in the backpack. The internal safety hook that can be attached to the pet's collar prevents the pet from jumping out. The reflective strip design makes night riding safer.