These thin, lightweight socks blend 25% brushtail possum fiber with 60% merino wool and 15% nylon to deliver exceptional warmth without bulk. Brushtail possum fiber features a smooth, hollow hair structure that makes it 55% warmer than merino alone and 14% lighter, while also being naturally antimicrobial and quick-drying. The result is a performance sock well-suited to hiking, travel, and everyday outdoor use across a range of conditions.