Note that this sling backpack can be worn on the left or right shoulder. What's good about this backpack is that if the main compartment is on your back and you slide the strap across your front to bring the backpack to your front, the zippers are facing up, kind of like they do in opening a purse from the top. This makes it very convenient to access items in the backpack without having to twist the backpack to access the zippers. That said, if you have a water bottle in the holder, it would be partly in the way of the zippers. The water bottle net can hold a bottle that is 2.75 inches diameter (I don't have one 3 inches to test). There is a clip for keys in the main compartment which is essential since you would otherwise have to dig down to find them. Also convenient is an extra pocket inside the larger compartment and another zipper compartment. There is a smaller zippered compartment that was large enough to hold my iPhone 11. This is a fairly small backpack, so when I needed to remove my light-weight hoodie, I really don't think I had enough room to put it in this backpack. I just tied it around my waste. Overall though, I'm pretty pleased with this backpack for short hikes where I don't need to carry a lot of stuff. Would love it if there was a cell phone compartment on the strap so you didn't have to access the backpack for your phone.Bought for Disney World trip upon reading great reviews. It was as expected. Shipped fast. Watch out though because I forgot the time when ordering (2 am) and when it said “delivered tomorrow” I was thinking that day?. Wish the mesh pocket was bigger. I Squeezed in my water bottle but it fell out when taking off the bag do probably any bottle would. The bottle Fits easily into the 2 larger pockets. I put my IphoneSE into the mesh pocket. A nook fits nicely but not an iPad. Very comfy on shoulder with the large padded strap. Nice clip for sanitizer or keys. Waterproof. Could fit umbrella or Think it will work great for me (5’4”) or my husband. This is the small sized one. I put it next to an older sling to show the size comparison (it has only one big pocket so everything jumbled inside).Bought two of these bags (different colors) for our kids to use when hiking in the Smoky Mountains. We originally were going to buy water bottle holders but these bags did they same, plus left a little room to store phones, a snack, etc. These are more versatile than a water bottle holder as well. Bags are small and can be worn in front or back - nice to have the option to shift carrying positions. They have since used the bags when shopping, etc - they're compact enough to not look awkward for that use. After roughly 10 uses the bags have held up well.These are clearly not designer or name brand sling bags; however, for casual wear or, as in my case, a great bag for a jaunt to take photos with my trusty little camera, it'll do quite well. I have a few sling bags by well-known brands, made with sturdier material. But I don't carry much besides my wallet, a hairbrush, and now, masks, in addition to my camera and many of them don't have an outside pocket for a water bottle and that's a feature I really like. The nylon fabric feels really thin, so I can only hope it won't tear, causing me to lose my phone or wallet, or my camera. Time will tell.This is one of the better man bags I have. I have a smaller Fanny bag and a regular size Fanny bag that just isn’t a bag I’m comfortable with. This one is better for all the medical stuff I carry but still a little uncomfortable because I can’t seem to get used to it across my chest or back. I tried wearing it over my shoulder but it keeps slipping. It’s roomy and I do carry my medical stuff and information in it. As well as my CC holder, wallet and keys for both my vehicles.I use this when I go on short hikes. I like that it holds a narrow water bottle on the side with room for small binoculars, snacks, bug spray, in the other two pockets. I usually wear in front so I have easy access to what I need, but hands free. Was a good solution for me.I bought this bag for hiking/walking with my dog. It fits a small jacked, keys, phone and poo bags. It also fits a water bottle but not in the exterior mesh pouch, which is one of the main reasons I bought it. The pouch is too small. I like the sling strap but I didn't realize it was for right shoulder only. Sometimes I'd like to switch sides on long hikes. It's quick drying and super lightweight.I use this bag on a weeklong trip in Disney World and a weeklong trip in Yellowstone. Wonderful little bag it was able to hold the essentials I needed. My only one the small complaint is that the water bottle holder is not large enough for my Hydro flask, 22 ounce. I had to use a Carabiner clip and attach it to the loop on the bag. Other than that great bag held up well.I was quite disappointed with this sling. The quality of the outter bag in decent. Behind the bag has this mesh that looks and feel like a mesh laundry bag from the dollar store.The main zipper on the outer bag is poorly placed, or maybe I should say that part of the bag is poorly engineered. The zipper when zipped down to open the bag zips all the way into the water bottle mesh holder. This means I CaNNoT place a water bottle in the holder without the bag unzipping properly. I have to remove the water bottle completely to unzip the big in its entirety. Also I would like to mention, the water bottle I have is very small and very short. That should give you an image of what is really happening.The next thing I have an issue with is that because this opening is on such a slant, it is hard to manage the bag without a lot of fussing and fumbling. I have a hard time in navigating my hands in and out of this bag. I feel frustrated every time I try to access something from it. To make matters worst, the compartments on the inner part of the bag are also all slanted and they are useless! I really mean useless. Because if the slanted pockets you are unable to fit anything properly in there. The quality of the lining of the bag is a joke. Again it feels like it was made in China and the material is flimsy. I am shocked to see all the positive reviews on this item.In the photos you can see where the zipper stops with the water bottle in the holder, and when I remove the water bottle the length of the zipper is further down.I use this EVERY time I go dog walking - I can fit my training lead in it, two balls, my keys (large bunch), hand sanitiser, poo bags and maybe a small bottle of water. It’s adjustable and I can loop the ball thrower through the top loop, and attach my treat pouch on the outside.I would have liked to have another side pocket, but it’s good and does the job I want. The reason I chose one shoulder is that I don’t have to keep moving it on and off my shoulders, but can just pull it round to use it.I found this bag super comfy to use with some handy little pockets and a keyring holder. My issues with it are that the water bottle side holder is so small I struggle to get my bottle in it with anything in the bag and it does look a little bigger in the photos than I find it's capacity to be. OVerall though for how inexpensive it is it's a good buy if you're only looking for something small (maybe good for a festival or dog walking etc).I bought this small bag for walking in carries all I need and is light and comfortable to wear. I can't say if it is waterproof as I haven't used it in the rain yet. I would recommend. The only comment I would make is that the numerous pockets and internal zips are not in the best positions for easy access and I have found myself searching through trying to items. This is minor and I admit particularly averse many pockets in any bag.An excellent small cross over bag to hold essentials plus a few extras secure for easy access. It's my 2nd one as used so much I wanted a change. Used every day for dog walking. Holds a small water bottle plus...plus. Don't look further. Very well made. A delight. Good price.