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 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. FOCUSED VERSATILITYThe Atom SL is designed to handle subtle climate shifts. Balancing air permeability with wind resistance, the shell material allows airflow during active periods, but helps cut the chill during static moments. 40g/m² Coreloft™ Compact insulation is highly compressible, insulates if wet, and delivers its superior performance for very little weight. All the Atom SL’s fabrics are selected to manage moisture and provide comfort while on the move. Sleeves are lined with a comfortable mesh, and lightweight fleece side panels help provide thermal performance and ventilation. Articulated sleeves and gusseted underarms extend freedom of movement.FUNCTIONAL MINIMALISMArc’teryx designers know that a thoughtful minimalism delivers more performance. Created to be so compact and light there’s no reason to leave it behind, the Atom SL employs only necessary features and ultralight fabrics. Comfortable, easily compacted and resilient, the Tyono™ 20 shell material uses fine denier yarns that allow a fabric configuration that is surprisingly strong for its weight. The DWR (durable water repellant) treated StormHood™ hood is uninsulated, making it ideal for minimizing wind chill or providing protection in light rain. The trim fit minimizes bulk and layers easily, and the insulation is placed only where it’s most needed, in the core, to reduce weight and bulk without sacrificing appropriate thermal performance. The result is a hoody that provides efficient shoulder season insulation, stuffs to the size of a grapefruit, and weighs a mere 260 grams.