"What Our Gearhead® Experts Are Saying:""I wore the GOREWEAR Concurve WS Insulated Jacket on a cold and gusty morning run where I would normally be layering two or three pieces, and it handled everything on its own at just 9. 5 oz without once making me feel overheated once the effort climbed. The PrimaLoft Active Evolve insulation adapts so naturally to changing effort levels that I stopped thinking about temperature management entirely and just ran.""Cold, windy run days used to require a negotiation between warmth, protection, and breathability that no single jacket could fully win. The GOREWEAR Concurve WS Insulated Jacket changes that calculation. Built around the new WINDSTOPPER ePE membrane by GORE-TEX LABS and filled with PrimaLoft Active Evolve insulation, it delivers total windproof protection and adaptive thermal warmth in a recycled lightweight nylon construction that comes in at just 9. 5 oz. GOREWEAR designed this jacket specifically for runners pushing hard in cold conditions, where the demand for breathability is just as high as the demand for warmth. PrimaLoft Active Evolve insulation is the performance centerpiece, adapting its thermal output to effort level so warmth stays calibrated whether the pace is easy or hard. The WINDSTOPPER ePE liner by GORE-TEX LABS is totally windproof and reliably breathable, blocking wind chill at the membrane level while allowing moisture vapor to escape efficiently. An air-permeable face fabric keeps the breathability stack working across the full jacket construction, and recycled materials throughout, from the nylon shell to the polyester fill, reduce the environmental cost of running in serious cold weather protection. This is the jacket that collapses a layering system into a single piece and performs better than the sum of its parts."