Active insulation polartec174 alpha174 insulation 40gm2 regulates warmth and transfers moisture perfect for active use with exceptional breathability run light stay protected outstanding warmth to weight ratio boosted by use of pertex quantum174 for windproof and water resistant protection increased durability a stable core of lofted knit fibres prevents fibre migration to keep a uniform consistency even after heavy wear and repeated laundering stretches with body unrestr