This is one of the best Hydration BackPacks that I have because it has a fanny pack attached onto it. This provides more room for thing while you are out camping or hiking. I could have used this couple of weeks ago when we went hiking because the other hydration pack I have did not have as many compartments as this one. This has an on and off valve where the water part comes out. I had to use a little force to push the valve but it worked. I love that it has this because I was not able to control the water from coming out with my other one when I would bend down to tie my shoes or sit down and rest. The top part of this is where the hydration bladder goes inside. There is a Velcro strap on the inside that goes through the loop on the pack. The arm straps are comfortable and light weight. The front part of this one zipper part that you can use for your small hiking tools. There is also two mesh net parts for water bottles. The fanny pack has two pocket sleeves that are perfect for bringing your ID and your partners. There is also enough room for you to place your cellphone in it as well. Overall, I would highly recommend this combo pack. You can get this Hydration Pack here http://www.amztk.com/hydrationpackrunningbelt I received this product at a discount in exchange for my honest and unbiased review.