The Kilpi NATHAN-JB boys' long-sleeved thermal T-shirt is made of quick-drying OPTI-DRY material, which is pleasant to the touch, extremely elastic, wicks moisture away from the skin well and thus maintains thermal comfort. The T-shirt has a round neckline. A seamless knit with flat seams and a snug fit that follows the curves of the body maximise comfort when moving and wearing. We offer NATHAN-JB in several sizes for the youngest and older boys. We also recommend getting the Kilpi NIEL-JB underpants as an ideal set not only for skiing, hiking, but also for other outdoor activities.Material composition: 53% polyamide, 41% polyester, 6% elastane