Nike One Women's Therma-FIT 1/2-Zip Mid Layer Bring on the cold. This heat-regulating mid layer is unbelievably soft and cozy while high stretch fabric keeps you ready to move. It's updated with thumbholes to give you extra coverage. Nike Therma-FIT technology helps manage your body’s natural heat to help keep you warm in cold-weather conditions. Thumbholes let you extend your coverage and help hold the sleeves in place while you move. Brushed fleece on the inside feels unbelievably soft while smooth on the outside.