Details Warm weather is never a constant, even in summer. Fog rolls in, a sudden thunderstorm blocks the sun, and changes in elevation and levels of exposure can cause temperatures to suddenly shift. But summer conditions seldom require bulky insulation. The men's Arc'teryx Atom SL Hoody is specifically created to hit the zone where insulation is required, but in a measured amount that suits milder conditions. Providing warmth comparable to a lightweight fleece for significantly fewer grams, the Atom SL is an efficient midlayer in cool conditions and a great standalone during rest breaks, early morning starts, and while enjoying the view from a freshly bagged peak. Material Exterior shell: Tyono™ 20, 100% nylon Coreloft™ Compact 40g/m² insulation Torrent™ 190 with Side panels: Polygiene® 84% polyester, 16% elastane Fit Trim Fit Hip Length Details Light, soft Tyono™ 20 has good air permeability; DWR finish repels moisture Coreloft™ Compact 40 synthetic insulation in the core provides warmth; uninsulated, mesh lined sleeves Low profile Torrent™ 190 fleece stretch side panels allow for ventilation Adjustable, low profile uninsulated StormHood™ No Slip Zip™ works like a series of speed bumps keeping the main zipper from self-opening Zippered hand pockets; adjustable hem Weight: 260g Arc'teryx Atom SL Hoody Men's