Size: S for 1-2.5kg dog; M 2.5-3.5kg; L 3.5-6.5kg; XL 5.5-9kg; 2XL 8-13kg. The dog backpack using canvas fabric, it is durable and strong.The backpack has a leash hook to prevent pets from escaping, is more secure, D-ring, which can be used for daily dog supplies like dog water bottle, travel bowl, poop bags, etc. The neck of the backpack is elastic, can flexibly adapt to the circumference of the dog's neck, comfortable and not stiff.Breathable: The front of the backpack carrier is equipped with a design of mesh, which is breathable without being stuffy. Four openings, the legs can be extended, soft and delicate hem, not hurting the dog's skin.Comfortable to carry: Added soft cotton pads on the shoulder strap and back to lighten the load; You can wear the backpack in the back or in the front.Service: We always support our customers and do our best to meet your needs. You will love this dog backpack and your pet will too. Product Description1---The dog backpack company is perfect for cats and small to medium-sized dogs weighing between 2.5 and 13 kg.2 --- Equipped with a dog leash hook , travel bottle D-ring, etc.3 --- Flexible neck, adjustable buckle to hold your pet better.4 --- With padded foam on the back and shoulder, more comfortable to carry.5 --- With zippers on both sides, easy for the dog to enter.6 --- Pets can stretch their legs easily, enjoy a comfortable journey.Don't hesitate, it's an ideal transport bag to take your four-legged friend for hiking, travel, a visit to the vet, etc.