Helly Hansen Lifa Merino Seamless ½ Zip and Pants

Our take 

Pair wool’s insulating power with synthetic’s wicking, and you get a garment that cashes in on both. Hybrids aren’t new, of course, but Helly claims the Lifa Merino’s unique polypropylene-elastane blend (woven together with merino) outperforms other synthetics as a hydrophobic fiber. Our testers agree: The set kept us comfy on humid ascents of Washington’s Mt. Shuksan and 50°F days in Missouri’s Mark Twain National Forest. Still, it’s warm enough for active use into the teens when paired with a light midlayer. Helly’s new “seamless” construction—the body, arms, and pants are made of single pieces of fabric rather than panels stitched together, which reduces the number of connection points—eases chafing and enhances stretch. Ding: Some testers reported the knees bagged out after a few days.

The details 

The pants’ smooth waistband never bunched or pinched under a hipbelt. Note: The slim cut helps pull sweat away from the skin, but those with larger body types will want to size up.

Trail cred 

“Over seven straight days of wear, these resisted odor so well I easily could have kept on using them,” one guide says. hellyhansen.com