When the water belt won't cut it
This pack is outstanding for a long run when lots of water is needed. The 2L bladder provides plenty of water and the slide top design is very easy to fill and to dry out afterwards. The pack keeps the bladder from bouncing around. Sometimes the pack pulls my shirt up in the back but as soon as I sweat a bit it the shirt stays in place. The pockets on the front are very convenient for some snacks or chapstick with room to spare. The clasp across your chest is easily adjustable but I find it could use two straps - one higher and one lower on my chest to really keep it all in place. It is a minor concern though. I have not had any rubbing at all from the pack and have taken it on several runs of 20+ miles. Overall a great water pack when my water belt just isn't enough.