I’ve gone through so many travel bags looking for the perfect one and this by far is the best so far. The fabric is really nice and my favorite feature is the pop out back. I just took my cat on a 9hr trek cross country and she had so much room once I popped the little tent. So easy to use. And all the pockets are such a great feature. It doesn’t even look like a pet travel bag. My cat was able to stand and sit up. I could tell she was so much more comfortable than when in her other backpacks. And this one fits perfectly on the floor. I have a picture under the seat without the pop out and with. The only thing to make it even more perfect….a pocket for my laptop!!The only issue I’ve had is that it is ripping on the zipper but my cat is also a fat boy so if your cat is over 12 lbs consider a different optionOur cat will reluctantly get in most of the time and enjoys spending time with us away from our dog. It gives home plenty of room and he can see what’s going on through the windows.FOR THOSE TRAVELING WITH YOUR PET....THIS IS GREAT !Sturdy, roomy, comfortable on your back carrier for small pets. My 11 pounds cat traveled comfortably for over 6 hrs in it . This carrier easily expands and folds back, zippers work easy. Light weight too. Worth the money.*Updated review* We purchased 3 backpacks and 1 was credited by the seller for an honest review.The design is very well developed. There are many conveniences for cats and humans built in. Aside from the mesh elements we rate the fabric sturdy and well constructed.The backpack is well ventilated. We placed mini fans into the mesh side pockets for extra ventilation and to provide a cross breeze. This ensured our cats stayed comfortable on 100+ degree Phoenix hikes.It was awkward to wear initially because it is boxy, but ergonomically our backs were spared on our week-long trip. The straps are well padded and sturdy.Don’t leave your cats unattended for any length of time in this backpack. I placed my kitten in the backpack with the expansion extended and stepped out of the room. I returned to find he had thrown his weight against the side of the backpack and was rolling across the room like a hamster ball.During the hamster ball incident our little guy’s bowels went liquid. As mentioned in another review, one of the two comfort pads are anchored down so we thought it would be a lost cause trying to get the stain and smell out. We are impressed how well the backpack held up to multiple power washes with the garden hose. Surprisingly, the comfort pad released all the stains and odor. The fabric shows little evidence of the event.Our 12lbs cat conducted an unintended pressure test of the backpack in it's expanded form. The mesh and wire frames collapsed and lost its form when he perched on top. We tried to coax and manipulate the wires back into it’s original shape to no avail.It’s perfect for the average size cat, just enough to get her to lay down and enough space for her to sit up. There’s a latch that keeps her in the carrier so she doesn’t get loose too. The best part was I got her through airlines without problemsI bought this because i saw a cat at the vet in one. I don't own a cat but my inlaws do. Their cats HATED it, but it’s more spacious and they can see more with it than their crate. It also has pockets, which their carrier crates do not.