A thermal reflective layer is printed directly onto the back of the fabric to reflect and retain your own body heat. The result? You stay 20% warmer. Rock it alone or layer it under your favorite shell for the perfect heat-regulating mid-layer. Four-way comfort stretch construction moves with you while advanced evaporation technology ensures that sweat is whisked immediately away from your skin to keep you dry and comfortable. A zip-closed security pocket stows energy bar, cash, keys and other essentials.