The 3d mesh material stays light and breathable on even the hottest runs and the extra stretch pocket keeps gels keys and cards safely tucked away plus you wonrsquot be stuck carrying a big empty bottle at the end of your runmdashonce the flask is empty just fold it up and tuck it away specifications collection running activity run user unisex hydration capacity 500ml17 fl oz hydration type quick stowtrade flask bpabpsbpf free yes gear capacity 05l30 cu in pack weight 10