The Rime Light IN Flex Hooded Jacket is one of Mammut’s more technical insulator designed for activities as demanding as mountaineering, ice climbing, and even backcountry touring. Its light insulation provides that special touch of warmth needed during highly active endeavors in the frigid cold, and unlike most puffies, this insulator stretches to move with you up the mountain. Also unlike puffies, the shell is air permeable, meaning it starts to breathe the minute you put the jacket on instead of after you start sweating. The shell is also water- and wind-resistant for light weather protection that pairs well with technical shells when snow really starts to fall. Pontetorto Tecnostretch fleece covers the sides and under the sleeves for better breathability where it counts. Mammut made the jacket with an athletic fit that ensures freedom of movement, and it layers under shells with ease.