Synthetic insulation does not have the same warmth to weight ratio as down insulation but it does keep most of its insulating qualities when wet. This jacket has 80g/m 2 of 100% supersoft Polyester insulation. The elasticated thread used in separating the chambers of the body & the arms provides a snug fit to reduce heat loss through wafting. Ideal for walking & hiking, or any outdoor activity where insualtion is required but where down products are impractical.