The Cotopaxi Acodo Hybrid Hooded Jacket puts synthetic PrimaLoft Gold insulation at the core and breathable recycled fleece at the hood, sides, and sleeves, so warmth stays put without slowing the arms down. It packs into its own internal pocket for the trail, making it the layer that's always worth bringing along. What Our Gearhead(R) Experts Are Saying:"I wore this on a trail run through a cold morning and never felt the sleeves fight a full arm swing, even picking up the pace on a climb. My core stayed warm the whole way, which told me the insulation was doing its job exactly where they put it."