Comfort begins next to the skin, and the Fjallraven Bergtagen Longjohns use a body-mapping design to boost comfort and performance. High-loft wool is placed on the knees, crotch, and rear for targeted warmth, while a wool and nylon mesh on the side panels, lower legs, and back of the thighs maximize ventilation and flexibility. The ankle cuffs are blended with elastane to give a chafe-free feel near the boot. Naturally odor-resistant wool helps keep you dry and comfortable as synthetic fibers increase durability and flexibility.