Under Armour O Series 9 Inch Boxer Jock Shorts Performance Technology: Under Armour HeatGear --For when it's hot. HeatGear technology wicks perspiration off your skin, rather than absorbing it. It's engineered with UA's Moisture Transport System to deliver core temperature regulation and maximum breathability. Anti-Microbial--Anti-microbial treatments provide permanent odor protection by inhibiting the growth of bacteria and mildew in the fabric. Ventilation--Mesh or breathable fabric inserts in high heat zones allow sweat to evaporate and cool air to circulate. Fabric Content: 90% polyester, 10% elastane