How does merino get so soft? Well for this Ortovox long sleeve base layer, it's the 19 micron fiber. There are 100 things we love about merino wool, it's moisture-wicking, it's anti-microbial, but one of the best things about merino is that it's a renewable resource. A once-a-year haircut for a sustainably raised sheep results in fine merino wool products to take on all of your outdoor treks.