Every great pow day starts with a solid (and breathable) foundation, so if you're after a lightweight underlayer to keep your lower half warm and toasty while reaping winter's rewards, look no further than the Burton Women's AK Power Stretch Pant. Made from a warm and breathable Polartec blend, the long jane-style underlayer incorporates a super stretchy lycra that will supplement your motion whether skinning uphill or going mach-sick down a line.