But right now, one of the leading Merino wool brands, Icebreaker, is on sale at REI. Icebreaker’s long-sleeve thermal top is an excellent layering piece that can be worn into the warmer seasons.
“My No. 1 recommendation for long underwear is merino wool,” says Sarah Savala, a gear expert and customer-care supervisor at the Seattle-based outdoor retailer Evo. “It wicks moisture away ...