SUITABLE FOR DOG. CAT OR OTHER SMALL ANIMALS: S and M size for choice. Suitbale for dogs. cats. puppy. kitten. chihuahua. rabbits. or more small animals. S size: 13.8x11.8x5.5in/35x30x14cm. Its recommended for the pet under 4.4Ib/2kg M size: 15.7x13.8x6.7in/40x35x17cm. its recommended for the pet under 8.8Ib/4kg. Perfect for outdoor. biking. walking. shopping. travelling or anywhere when you keep your pet with you. KEEP YOUR PET VISIBLE: A drawstring opening neck hole on the top of the backpack to keep your pet stick their head out.make them ventilation and visible. enjoy the entertainment with their host. adjustable hole string and soft mesh padded hole edge to ensure its comfort SECURE & COMFORTABLE: Our pet carrier design a hook inside for hooking pet's collar. prevent your darling falling from the pet carrier bag and makes him or her feel comfortable inside BREATHABLE & NON TOXIC: This pet carrier backpack is made of high quality canvas and mesh fabric. breathable. comfortable and not stuffy. non toxic and durable. provides a portable cozy bed for your pets. universal for the four seasons PADDED & WIDE SHOULDER STRAP. TWO POCKET FOR STORAGE: Design with widened adjustable shoulder pad to help reduce load and increase comfort. Two retractable buckles on the bottom to prevent shoulder strap deviation and maintain the stability of the backpack. Mesh side pockets help store leash. whistle. water. snacks. treats and other necessities