Even In Summer, Warm Weather Can Shift Quickly To Cool. Superlight And Packable, The Atom Sl Anorak Provides Just The Right Amount Of Insulation Required To Handle These Subtle – But Noticeable – Drops In Temperature. Strategically Placed At The Chest And Back, The Coreloft™ Insulation Is Efficient, Light, And Compressible. The Tyono™ 20 Outer Balances Airflow With Wind Resistance, A Dwr Finish Repels Moisture, Stretch Fleece Side Panels Ventilate, And An Uninsulated Hood Adds Coverage.