We're ushering unders into the future, with our revolutionary Temp Tamer Modern Brief Underwear! Crafted from thermoregulating 37.5® Technology fabric, these briefs keep your body at the perfect temperature, warming you up when you're cold, cooling you down when you're hot. How does it work? Who knows! Just kidding, it's science. The odor-fighting, moisture-wicking fabric is embedded with volcanic minerals and activated carbon that uses your body's own infrared energy to regulate your temp.