A few years ago, Ultimate Direction changed that by combining running vest comfort with backpacking capacity for their Fastpack 20 and 30. Ultimate Direction is best know for their running vests and hydration products that are used by some of the world’s elite ultra runners. This year, Ultimate Direction has released a revamped lineup of packs they’re calling the Trail Collection. This includes the Fastpack 15, 25, 35, and 45. For this review, I’ll be taking a look at the 35 and 45.