"Purchased my second pair - totally worth the price"
I've used all types of base layers - synthetics, wool, thin, thick, etc. These are perfect on every front. They're incredibly warm and perfect for high-altitude aerobic activity. They're not so thick that they're suffocating, but they're not so thin that you get cold close to the summit. The merino wool is incredibly soft and not itchy at all, and they won't stink like synthetics. An excellent excellent product and the go-to base layer for any mountaineer.