[Le Coq Sportif] Long Sleeve Mock Neck Practice Shirt Light Absorption Heat Sweat Absorption Stretch UV CUT (UPF) Practice HEATNAVI Women's QTWWJB03Material Secret of warmth is light active thermal insulation material HeatNavi's biggest feature is that it completely absorbs almost all the wavelength range of light and generates heat Design Function Mocked with medium weight shirt material The neck design gives it a luxurious finish. It is an item that can be worn alone in the fall and as an inner layer for outerwear in the winter.