Columbia's Omni heat reflective lining and Omni-tech is better explained as a dual system that aims to keep you nice and warm (as your jacket should do), while also ensuring you don’t overheat. Since Columbia designs most of their gear for activewear, they’re expecting you to hike, run and climb in their jackets, so regulating body temperature is important. This technology has a thermal reflective lining using metals like silver and gold, thus keeping you warm. This also means that their jackets for men and women get toasty, fast. Therefore, Columbia also uses a breathable shell for air circulation to help you regulate your body temperature better without overheating.