Updated review after a 70 minute trail run. I run a lot. Like, every single day on over a year streak kind of “lot.” A few times each week I also run a lot, defined as 2 or more hours on a run kind of “lot.” This many miles and daily abuse is brutal on gear. Update: I clearly condone Nathan products. Except after a 70 minute trail run, I found some really annoying attributes. The bite valve can be a bit tricky on the run. The bottle is stiff, and squeezing water can be tricky due to the stiffness. The holster is soft and collapses, so it is hit and miss replacing. I had to come down to a walk several times to replace the bottle. The flexible cord to lock in the bottle can be tricky as well. I switched out bottles and caps from other Nathan products. Nathan products have never let me down. Well. Ok, that’s not completely true since my previous Nathan belt is having failures with zippers and tears. But hey, after 8 years in service, and worn on at least 3 ultra marathons, that’s hardly “failure.” Delighted with this replacement. The pouch can hold a phone (previous model could at first, but phones grew over 8 years…), and the flasks are standard 10oz with squeeze spouts. Each bottle has a retainer flex loop so all stays secure. For me, the bottles are spaced to ride just on the hips, and having phone and gels in small of back is a comfortable place for them to ride. Belt holds well and band has some flex. Some reflective strips on the the bootle holster. I use hydration vests too for more water capacity, but sometimes it is just nice to not have that burden on the back, or if water stops are frequent enough for 20oz to be enough. 20 oz is not much, but on a well planned training route or in a race where the bottles can be topped off and in between water points, and for the motion of RUNNING, then this belt is a good piece of gear. Most people sweat - on average, but can vary widely based on environment and amount of conditioning - at a rate of 24 to 32 ounces an hour while exercising—and should aim to replace at least 75 percent of that on the run. That means drinking 18 to 24 ounces an hour while running, so 20 oz is in that sweet spot for a trained or conditioned distance runner. Research, and my personal experience, shows, peak water absorption on the run is 5 oz sips every 10-50 minutes. More than that is water belly - or worse pit stop in the bushes - on the run. If you are looking for a canteen for a hike and expect to guzzle water, then this belt ain’t your gig. This belt is distance running gear to maintain hydration, and designed for that specific purpose. I went through all of that since I notice frequent complaints on these types of belts with 10 oz bottles from non distance runners. They are not wrong for hiking and “exercising” - but they definitely are critiquing this tool for the wrong job! As warm weather begins to loom on my long runs, even the early early ones, so glad to have a hydration belt back on the equipment roster for hour runs or runs that allow top off at hour intervals. As always, thumbs up on Nathan hydration products, but I dropped a star due to annoying attributes listed above. I really recommend for trail use the more expensive trail version (which is still 20 oz total of water, which is more or less the “standard” for belt hydration).