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