29480 Arcteryx Women's Atom SL Anorak 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 resistnace, a DWR finish repels moisture, stretch fleece side panels ventilate, and an uninsulated hood adds coverage.