What Our Gearhead(R) Experts Are Saying:"I wore this on a chilly trail run and switched it from neck gaiter to headband halfway through as I warmed up. The merino wool never got funky, even after a full day of sweat and wind."A good gaiter should work as hard as you do, and Mammut built the Tree Wool Neck Gaiter to prove it. The natural Merino wool and Lyocell blend regulates temperature through a brisk hike or a sweaty trail run, shifting easily from neck gaiter to headband to facemask as the wind picks up or the sun breaks through. Odor neutralization comes built in, so it stays fresh trip after trip without ever needing a wash.