This item gets a lot of high marks but didn't work for me. Firstly, the belt is too thin at 1 inch wide(as mentioned by other reviewers). For it to be comfortable and able to support some weight, it should be at least 1.5 inches wide. Secondly, the water bottles are kidney shaped and fit the slots perfectly. However, if you want to use insulated bottles by different manufacturers, chances are they won't fit...and if they do, their girth will impede into the main compartments.
Good design, well made, I'm pleased with it overall. My only complaints are that the "holsters" for the water bottles don't adjust to accommodate slightly larger standard-sized water bottles like Nalgen, and it's a bit pricey given the size. I'd like the belt strap to be wider, but it's not a big deal for me. Should be durable and dependable.