Terrific underwear. Comfortable. Does not stink.... merino wool wicks moisture away from your skin, so if you get wet, or you sweat... (pee? Not as much) They hold up well. I had two pairs of merino wool undies, these and another brand or style. I wore one or the other every day for three months. No stink, they held up exceptionally well.  They are pricey, but absolutely worth it. For travel and trekking, for me: there is no other underwear I'll take. Synthetics? Iv'e got some that are pretty good for travel because you can wash them out.... These are significantly better.
One thing. They run large and they stretch. As an American who wears 'Large'  I know I'm really a Medium, but medium is usually too tight. I bought a third pair of these in the UK, I bought Medium--the fit is perfect. (Is a UK Medium the same as an American Medium? probably)