Our best-selling CirrusLite now comes in a duffle length for maximum warmth. Premium Down insulation protects you—from the top of your head to below your knees—against sub-zero winter weather. NOTE: Temperature ratings are based on a controlled laboratory test by an independent university lab. Also consider: your sensitivity to cold and wind-chill; time of exposure; activity level; and use of layering. Models shown are 5’9" to 5’11" tall, wearing size S/4, L/12, or XXL/18.