The Men’s Balder Zip Is A Technical Mid-layer With A Streamlined Design That Will Keep You Warm On The Coldest Days Of Winter. Balder Has A Minimum Of Extra Detailing To Make It Move And Work Effortlessly Under A Shell Garment. The Inner Layer Is Comfortable Against The Skin And Stretchy To Ensure Good Flexibility, With Thumb Loops To Keep The Sleeves In Place. The Fabric Is A Mix Between Polyester And Recycled Wool, Which Makes It Durable And Soft.