The Arcteryx Proton Lightweight Hoody is a super light insulating mid or outer layer designed for spring and summer conditions when you may need a little extra warmth. The Proton Lightweight is made from 20 denier Fortius Air 20 outer which is impressively durable for its low weight. Fortius Air 20 balances air permeability for breathability when you are working hard, with light wind resistance. The insulation is a light layer of Octa Loft knit insulation which provides very breathable warmth. The Proton Lightweight is the ideal hiker or climbers jacket for when the valley bottom is hot but higher and more exposed terrain is much cooler. The Proton Lightweight is breathable enough to be worn all day, but at just 343g (medium) its light enough to go in your pack for emergencies. The Proton Lightweight features and adjustable insulated hood that will go under a helmet. There are two zipped hand pockets and one zipped chest pocket. The Proton Lightweight is trim fit with articulated patterning for freedom of movement. This is an excellent climbers and hikers layer for those unpredictable spring and summer days. Arcteryx Proton Lightweight Hoody Features Fortius Air 20 outer Octa Loft knit insulation Adjustable low profile hood 2 zipped hand pockets 1 zipped chest pocket Bluesign Approved material Fit:Trim Weight:343g Arcteryx Proton Lightweight Hoody