Outdoor Researchs best-selling Vigor Collection is guaranteed to help you layer intuitively and effectively for cold weather adventures. Thermo-regulating ActiveTemp works hand-in-hand with Vigors grid fleece fabric, which wicks sweat and allows total breathability when youre gunning it uphill. Whether youre wearing it as a midlayer for sub-freezing days, or an outer layer for mild temperatures, take on each adventure with Vigor.