Castelli Flanders Wool Long Sleeve Base Layer: A long sleeve base layer with a soft merino wool fabric construction. Featuring flat seams for comfort & a high collar for additional warmth. Ideal for cold weather rides. View a larger copy of this image for a more detailed view. 18-gauge merino wool fabric 4-needle flat-lock stitching Mock turtle neck for additional warmth Flat finish bottom 159g (Size L)