Merino wool regulates body temperature, is comfortable and doesn't smell bad even after you've worn it multiple times. In fact, it's better to wash it as little as possible. These properties make it ideal for wearing against the skin and perfect for long expeditions where you have limited space in your pack and no access to a washing machine. Merino wool has become tremendously popular over the last few years; it's not cheap, but once you purchase a few pieces of merino underwear, you'll wonder how you ever went without. Naturally, we sell several bras made from merino wool that are designed for more strenuous physical activity like hiking or climbing.