Warmth The Hummingbird’s barely-there, ribbed fabric works like a mood ring of baselayers. In cold weather, the web-like knit traps body heat, which kept one tester warm during a very cold (-13°F), snowy Mt. Whitney climb. In warmer temps, it lets air move through freely. “I stayed dry while hiking hard and warm in camp,” a tester says.
Fit It’s made from Montana-sourced Rambouillet wool (from a French breed of merino better suited to the U.S. climate), which features natural stretch that clings “just right.”
Drying Thanks to the light construction, its drying time is nearly comparable to synthetics.
Durability Testers reported some thinning around the shoulders after a season of hard use under a pack, and its delicate knit demands careful treatment.
$80; 5.6 oz. (m’s M); duckworthco.com