This is probably the single most wonderful item of clothing I’ve ever owned. It’s 100% Merino wool. Soft, useful, light, washable, warm, stylish. I’ve been wearing this whenever it’s cold, over a cotton or silk t-shirt. Or if colder, over a lighter weight Merino wool shirt.
I used to wear mostly natural fibers. Then along came Patagonia and other outdoor outfitters with some great artificial (usually polyester) products: fleece, Synchilla, Capilene, warm lightweight coats, polyester shirts for travel that could be rolled up in a backpack, and look wrinkle-free when worn.
Now I’m back to layering with natural fibers. 100% wool in various combos works wonders. Icebreaker has an elegant line of products (in spite of the very weird cover photo on their home page). They have testimonials from athletes who wear Merino wool clothing in various combos (there are 3 weights): climbing Everest, on kayak trips, wet or dry, hot or cold. How great, natural fibers outperforming artificial! Also check out Smartwool clothing, another line of beautiful Merino wool products. Go to Backcountry and do a search for “smartwool.”