What Our Gearhead(R) Experts Are Saying:"When I'm scrambling ridgelines or racing through alpine trails, I don't even notice I'm wearing the Trilogy Sky Vest-it moves with me and keeps hydration and tools exactly where I need them."Made for fast, high-output days on technical terrain, the Millet Trilogy Sky Vest 5L is a featherlight hydration and gear solution that doesn't compromise performance. With just the right amount of space for essentials, this 5L pack was born in the mountains and refined through alpine endurance efforts. Whether we're trail running in exposed zones or pushing the pace on a solo summit bid, it delivers unwavering stability and smart access on the move. Durable Dyneema(R) construction and 4-way stretch panels give this pack a snug, bounce-free fit that adapts to our movement. The integrated hydration compatibility, pole and ice axe carry, and mesh stash pockets keep fuel and gear right where we need them-secure and within reach. Adjustable chest straps help fine-tune the fit, making this small pack ideal for steep missions when ounces count and balance matters.