When North Face engineered the L3 Ventrix Hoodie they sought to create the ultimate alpine layer for a wide array of activities. What they came up with is pretty darn close. This lightweight, compact, synthetic hoodie will keep you warm only when you need it. Activated by movement, this piece features an innovative ventilation system that will regulate your temperature when your heart rate spikes. So next time the mountains come calling, make sure you answer the call with the Summit Series from North Face; designed for the harshest alpine environments.