I don't bother to write many reviews but I did so much research on bags of this type that I really took note of its functionality during a recent August week in Walt Disney World. With a few minor quirks, this bag functioned just as I had hoped. Since it was a summer trip, it needed to function in hot and stormy weather and carry an insulated water bottle. It fit my 18oz Yeti rambler and I had ice all day in 100+ degree heat. Carrying a bottle of that size did affect available space in the bag so be aware, and did require the elastic cinch around the lid to keep it securely in place - and it did fall out once in a 6 day trip. The bag also kept my items dry during daily downpours, but be aware that the strap will get wet and stay wet - a bit of a shame as that's where I kept my phone. On that note, my iPhone 15 pro max with a substantial bumper case did fit in the strap storage which was an important consideration for me. I did use the quick access storage on the strap (behind the phone) one time and almost immediately had the item fall out after going through security so I didn't use it again. As for storage, I pack to be prepared and I was able to fit a personal fan, hard sunglass case, foldable boonie hat, hand wipes, poncho, cooling towel, and a case of medications along with the aforementioned yeti bottle. This was about maximum capacity, but was everything I needed, and I was able to get my phone/wallet etc in as well when required. It did not feel overweight…