Climb, run, hike – choose your day. An insulated hoody created to give you the freedom to explore your way, the light, durable Proton’s breathable thermal protection delivers comfort across a range of temperature and output levels. Octa® Loft knit insulation provides warmth and allows airflow to help regulate comfort. Abrasion-resistant Fortius™ Air 20 fabric stretches, resists wind, and breathes. Articulation aids mobility, and the low-profile insulated hood fits comfortably under your helmet.