Cold mornings and hard efforts require a layer that can handle both ends of the equation. The Nike ACG Therma-Fit 1/2-Zip Top opens with soft fleece construction powered by Nike's Therma-FIT technology, trapping body heat when the temperature drops while the high-stretch polyester blend moves freely through every rep, stride, and overhead movement. The standing collar zips at the neck so we can open it up the moment our core temperature climbs. What Our Gearhead(R) Experts Are Saying:"This is my go-to for early morning runs when the temperature hasn't decided what it wants to do yet. Side slits at the hem add just enough give for full stride without the fabric riding up. Solid cold-weather layer that earns regular rotation."