This vest is a 'must-have' piece for any outdoor enthusiast – perfect for layering with your favorite shell or wearing as a stand-alone performance layer. With ECOLoft™ Air SR Insulation, the Sirdal jacket has an optimal warmth to weight ratio. Its light, relaxed-fit enhances your ability to move in nature in changeable conditions. The smart synthetic insulation also avoids clumping when wet, unlike traditional down fill. The outer fabric is ripstop and built to last.