This is for smaller phones, like the iPhone 1-4, the iPhone 5 might be too long. If you have a very bulky phone, don't buy it. It works perfect for what I have. I have a Samsung Eternity, and it has approx 0.7 centimeters of extra space in length.
Spill-proof. 100% polyester. Lightly padded case, it's not an otter box though, do don't go throwing it off a two-story building.
I bought a Dakine backpack too, and it fits perfectly on the shoulder straps. It should fit any brand of backpack (The North Face, Volcom, etc). It doesn't really slide up and down the straps, unless I deliberately tug on it, which is good, or unless I hit major bumps on my bike.
I bought this to use with my iPhone 4s and my Lifeproof case while canyoneering. The lifeproof case doesn't fit in there and the iPhone 4s barely fits in there. I ended up returning the case because it doesn't work for what I needed it for. It's a good case though for school or work.
I really really liked the idea of this case, but I'm not pleased with the final result. I'm sure it would fit some of the older, smaller smart phones and brick phones, but there is no way you're getting an Android or other similar phone in this case.
If you have a protective case on your iPhone, forget it. The phone will come out and over the zipper. If your iPhone (4 or 4S) is naked, it will BARELY fit, and zip over the phone.
Cons: WAY too small
Pros: 1-The felt lining is awesome. Very soft and protective
2-The Phantom color is super sweet
3-If you have a smaller phone, your phone will be wrapped in awesome protective goodness.