I purchased a Mountainsmith Lumbar pack that holds (2)32oz Nalgene bottles. I think it's no longer manufactured. I found it a bit heavy and cumbersome with both bottles full and the pack loaded so I bought some suspenders to take up some of the weight. This works out well and is a lot more comfortable. I also have a Maxpedition Proteus that I like a lot better. It's smaller and if I'm out on the trail all day I use a CamelBak with it for hydration. It just depends what I doing as to which one I use.