Designed for multi-day running, the Ultimate Direction Fastpack 30 is a unique ultralight pack. With a volume just big enough for a two-night load and an ergonomic shoulder harness system resembling a vest, this pack is the only one we tested that is quite comfortable when running. Lots of pockets on the front of the vest (including two that accept water bottles) allow you to free your waist and hips for running and keep snacks, water, maps, and your phone at your fingertips. Anything north of 15 lbs gets hard on the shoulders really quick, but light loads carry well with very little bounce.
The Fastpack 30 has no close competitor in our review. While overnight trail running is a small niche in the ultralight world, this is a perfect pack for it.