Under Armour Heat Gear Ultra 4" Compression Short Womens Fit: Compression--Supports your muscles to prevent fatigue during intense training. Fabric Type: Microfiber--Soft, lightweight fabric with a silky feel, designed from very fine synthetic filaments 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. Ventilation--Mesh or breathable fabric inserts in high heat zones allow sweat to evaporate and cool air to circulate. Flatlock Stitching--Seams are sewn flat to the garment to enhance durability and prevent skin chafing/irritation.