What Our Gearhead(R) Experts Are Saying:"I wear this under a shell on cold days when I know I'll be working hard enough that full sleeves would just make me overheat. The core stays warm while my arms stay free to move, which makes a real difference when I'm scrambling or using poles."Sometimes a jacket is more than the moment calls for, arms working hard enough to generate their own heat while the core still wants some insulation. The Microlight Vest splits the difference, wrapping the torso in recycled 700 fill power down while leaving the arms completely unrestricted. Zoned micro and nano baffles keep insulation lofted evenly across the chest and back, and a drawcord hem seals warmth in without adding bulk at the waist. It packs down into its own clip-in pocket just as easily as the full jacket, making it just as easy to stash away the moment the pace heats things up on its own.