This pet carrier backpack is designed for carrying small dogs/cats, S for 3.5-5.5 lbs, M for 5.5-9 lbs, L for 9-15.5 lbs, X-L for 15.5-21 lbs. Please DO measure your pets and choose according to the size chart. Pet-Friendly Ease: Keep your pet safe and comfortable with Legs-out and tail-out design; Hook and loop, safety buckle, zipper and elastic openings could be provided a comfortable and balanced fit for your dog; Breathable materials keeping your pet dry and easeful. Comfort for you: A hands-free pet carrier with comfort pads, effortless wear with hook and loop closure, smooth zipper. Two Different Wearing Ways: You can wear the pet carrier on your front side or back size, it keeps you easier to take care of your pet and ensures a secure and comfortable fit for your dog or cat. A win-win solution allows both you and your lovely pet enjoy outdoor adventure. Choosing Size: Before purchase please checking and confirming the distance between the DORSAL LENGTH and BUST of your pet; Please determine the correct size basing on our size chart. If you have any questions about choosing the size, please feel free to contact us. ABOUT US: UTOPIA ALLEY is a woman-owned and operated business. Our goal is to provide our customers with furniture, home decor, essentials, and accessories made with durable products and exceptional craftsmanship. We believe in creating a stylish, comfortable space where you can relax, recharge, and feel inspired.