Arc'teryx Proton Hoody HommeMade for climbers but not limited to rock and ice the Proton Hoody is the go to breathable insulation layer for high output mountain missions. 80gsm Coreloft Compact insulation works with the air permeable face fabric and liner to regulate temperature and vapour build up. The Fortius Air 20 nylon shell is light and durable, articulated patterning removes restriction, and a helmet compatible insulated hood extends the warmth.