Review: HyrdaPak PackFlask

For the fastest, most efficient movement, trail runners and speed-hikers want quick access to water, without the weight or bulk of a Nalgene—and that's exactly what HydraPak's new PackFlask offers. Fully collapsible, with a minimalist sheath that straps to your shoulder strap or vest for on-the-go hydration, the PackFlask also has a built-in water filter. So no matter where you are, safe water is always at the ready. Which means you can carry less, go farther, and filter on the fly. $72; hydrapak.com.