This BRAND NEW one I just bought - the strap broke in the airport after only carrying it 10 minutes - not happy! My old one lasted for years without doing that. I had to rig it to make it work so I could complete my journey. Though my old one is FIVE stars, I would take off 2 stars for the strap on this new one. I hope the company will make it right. -- Update 3: I bought a new one (Original Deluxe) in black and lil Bear loves this one more than the original one. It has more mesh for air (not shown in these pics) but otherwise is very similar to the Delta Black one I had. He actually got in it and took a nap--I was surprised! Still a good buy for the money. Bear is about 15 pounds and is a long-haired chihuahua mix - stocky build - he JUST fits in it. I could go for a large but he is able to turn around, lie down comfortably, and walk in it just fine. I like this one even better than the first one. --------- Update 2: Travel. Lil Bear and I did great together with this Sherpa Carrier. I hauled him around the airport easier than I thought, though it killed my shoulders and back to lug around his carrier and my other carry on, but that's travel. We went through the security line with no problems at all. And, the carrier fit under the seat perfectly. Lil Bear lay quietly the entire time (but he is a well-behaved awesome calm dog). The medium just fit - I mean JUST fit. I considered whether I should have bought a large but then that would have been too big. So measure your dog and look at the dimensions of the carriers and go from there. ----------- Update: I just found the other pocket on the other side! So two pockets! This is a very well-made/constructed pet carrier that I bought for less than I thought I'd have to pay for such a nice carrier! The 'canvas' is made of quality material and the seams are firm and intact. There are handles so you can hold the carrier in your hands, or you can use the included strap to put it across your shoulder. There are two openings to the carrier: one on the front, and one on the top. The zippers are heavy-duty and well made. There are also air vents - one on the side, and one on each end that you can unvelcro the covering to provide that air vent. Inside on the "floor" of the carrier is a nice padding that will detach for laundering. On the side is a zippered pocket. That would be my only "negative" to this - I wish the pocket were a little bigger so I could fit a little more in it, but it would fit some treats and a regular leash. A bigger deeper pocket would be nice, but that's not a deal breaker at all. THE SIZE ISSUE: - Besides wanting the pocket to be a little bigger, finding the correct size can be a little confusing. I researched so many reviews before purchasing, and the sizes and poundage were all over the place for a medium carrier! Argh! I knew I didn't want a small, but deciding between a large and medium was daunting. I went with the medium and he fits, but it's close. It's why the 4 stars instead of five, though I'm still tempted to give it 5 stars, but maybe some videos and pictures from the manufacturer would help. If you are confused about finding the correct size, I can only tell you that my dog is a long-haired chihuahua but mixed with something else - he's about 14 pounds, and about 10 inches high or so--measuring him from feet to shoulder/back height, length about 19-20 inches from nose to back (not including tail of course!)--these are approximate as it's more difficult to measure a dog than I thought (laugh). He fits inside the carrier with enough room to turn around but it's close - he can stand but it's very close - he'll be lying down 99% of the time and he should feel secure and comfortable. I have no idea about under the seat issues, yet, because this will be my first time to fly with a pet. The large may have been too large where he is kind of shuffled around in there - I felt the medium gave him some security from being "knocked about." I don't know if this helps, but I do suggest ordering early enough that you can not only train your dog to be comfortable with the idea, but also to gauge the size. My dog is a chihuahua-something-I-don't-know mix, and is about 14 pounds. He's about 10 inches high. He fits in it just fine. I didn't want him to have so much room that he was "knocked about" as I carry him, but he has enough room to stand--but just enough to stand, and he can turn around in it. The small would have been way too small, and the large would be too large. But he fits closely and I'd not want it any smaller than this. Surprisingly, the weight when you carry him even if you use the shorter straps on your shoulder isn't bad at all. Some Tips for getting your dog used to the carrier: They include a little tag with some tips. I did my own thing, too. If your dog is not used to a carrier, some things you can do are: I did these things one or two times a day only: Make sure the carrier is associated with something good - way long before your trip is to come, you should start preparing your dog so he isn't scared of something new. I started early on by putting a treat inside the carrier and put the carrier by the side of his bed. I just let him go in and get it without me closing him up. I did this for several weeks, the only difference is that after a couple weeks of doing this, I gently nudged him in and closed the front "gate" but didn't zip it-I petted and praised him. Doing this a few times, whenever I'd pick up the carrier to bring it over to his bed even before I opened the treat can to put in the treat, he'd be excited, knowing he was going to get a treat. Then next stage I put the treat in there, but I closed him up. Did this a couple times, reaching my hand through the top part and petting and praising him. The next stage, I closed him up with the treat and carried him around my house, talking to him in a happy voice. This is the stage where I am now. By time my flight comes, he'll be very comfortable inside there. I'm also going to take him in the car and drive around with him in it. He's a calm well-behaved dog, so I don't expect any problems at all. If I have problems once I do take my trip, I'll be back to report that. I do highly recommend.