Review on Running Expandable Pockets Sweatproof Rainproof by Demetrius Patsion

Bought to hold a (large) car key and 2 gel packs while running. It's so light and fits so well I don't even feel it. It's also nice to have something other than the waistband of my shorts to attach my music player to. The way the pockets expand is really impressive. I think you could put your phone in there, but I like to keep my weight to a minimum while running. As far as carrying a giant car key and a small amount of fuel, it's absolutely perfect.