Lightweight and highly breathable, this next-to-skin liner is made for moisture management, soft comfort, support, and freedom of movement on mountain runs and high-output adventures. The Fortius Air 20 stretch mesh allows airflow, low-profile seams minimize irritation, and the anatomic shaping and articulated patterning elevate comfort and mobility. The pull-on design and streamlined fit layer comfortably under shorts, and a small drop-in pocket holds gels or other essentials.