Minimalist marathon runners rejoice Amphipod's Stealth Runner Hydration Lumbar Pack is here to serve. Its included Hydraform bottle makes this pack suitable for 5K and 10K events, and there's a side pull access and a Jet Squeeze cap for quick and easy drinking. The AirStretch belt is comfortable, stretchy, and forgiving, and there are AirFlow mesh panels for ventilated breathability. There's a front pocket that expands large enough for most smartphones. Reflective detailing helps keep you visible in low light.