The Jersey  Kilpi NATHAN-JB boy's long-sleeved thermal jacket is made of OPTI-DRY, a quick-drying, pleasant to the touch, extremely elastic material that  wicks moisture away from the skin and thus maintains thermal comfort. The shirt has a round neckline. The bust part  it is seamless while the sleeves are sewn with flat seams to not irritate the skin. The fitted cut that replicates the curves of the body,   maximizes comfort during movement. We recommend the combination with the Kilpi NIEL-JB thermal pants  as a great set for skiing, hiking or other outdoor activities.