Unlike regular wool, merino wool contains superfine fibers, providing non-itchy warmth - exactly what you want against your skin on long backcountry tours. The Icebreaker Men's Apex Leggings with Fly insulate during cold-weather activities and regulate your temperature once you've warmed up. Quick-drying and exceptionally soft, this base layer keeps your legs dry and comfortable on all day excursions. With a gusseted crotch and no back seam, you can move freely whether you're hiking, skinning up, or dropping a knee on the way down. Your first layer of defense against the cold, the Icebreaker Men's Apex Leggings with Fly are a premium, natural base layer. Merino wool provides breathability, odor-resistance, and quick-drying action Exceptionally soft and warm base layer for all day comfort Midweight for cold conditions Gusseted crotch offers mobility No back seam enhances comfort Front fly for a fumble-free pee in the backcountry .