ThePines Microgrid Ultra - Lt Baselayer Bottom manages our body temperature and moisture during our favorite high - alpine adventures. The fabric blend of partially polyester and spandex provides lightweight warmth and comfort in an package, while its smooth face slips easily inside our bibs, and its plush, microgrid backing wicks away our sweat. Plus, the addition of HeiQ Fresh Ffl odor control technology keeps us feeling and smelling fresh during a weekend trip.