Review on Gore Wear Windproof Windstopper Turtleneck: Ultimate Protection against Wind and Cold by Kyle Rose

Probably the most expensive undershirt, but I'm super satisfied. I use the shirt for road cycling and have worn it at around 10 to 20 degrees with a cycling jacket over it. The shirt really doesn't let the wind through, keeps you nice and warm and dries very quickly. That's great because I don't wash my shirt after every ride.