Mountain Hardwear Geist Jacket 100% Nylon Provides superb flexibility without sacrificing comfort for warmth, or warmth for comfort and flexibility. The perfect example of simple, high-performance gear that is as kind to Mother Nature as it is to you. Resists moderately inclement conditions and makes an excellent lightweight layer for even colder conditions. Made with ultra reflective print and material to keep you safe and visible on late night runs.