With its vapor-transferring close fit, the Merino wool I/O Bio Boys's Contact 1 Tight ensures dry, nice days If you're charging the steep and deeps of winter, or biking in Moab slick rock in spring. As an excellent next-to-skin layer, this super fine, never itchy, and body-odor resisting tight hugs you comfortably, while I/O's merino wool regulates temperature unlike any other textile, I/O also uses P-9 woola vertically integrated supply chain that ensures quality performance and equality in the marketplace.