What do you get when you cross the 2-layer insulating technology of outerwear with merino wool? The Helly Hansen Lifa Merino Midweight Base layer Pants of course. These warm winter accouterments have a 100% merino wool exterior that delivers plenty of warmth in cold weather, while and moisture-wicking Lifa fabric interior adds breathability against sweat. These close-to-body long johns are so adaptable to temperature changes, you’ll forget you had them on!