Breathes like a feather. Feels like a fleece. The Aerothermal 1/2 Zip gives you next-to-skin comfort and super-light, breathable warmth for active layering. PrimaLoft® Active Evolve synthetic insulation mimics high-loft fleece softness without the bulk while boosting temp-regulating powers. All the cozy warmth without all the weight, this breathable layer allows you to shed heat without shedding layers for fidget-free comfort on the skin track, trail, or daily commute. A lightweight ripstop outer fabric adds an extra layer of toughness for brushing off rocks, branches, or jumpy pups, with hand pockets for phone, keys, wallet—or warming your hands between sends. Raglan sleeves and a healthy dose of stretch cement this midlayer as an all-day, all-year, all-activity go-to for active pursuits, with standalone comfort and warmth for off days or even the office.