Under Armour Women's Locker 2.0 Short Sleeve Shirt 100% polyester fabric is ultra-soft & smooth for extreme comfort with very little weight tretch-mesh back panel delivers strategic ventilation 4-way stretch fabrication allows greater mobility in any direction New Fit: +1" Across Waist, +1/2" Sleeve Length Locker loop makes it easy to hang It's designed to fit tight to your skin, under your outerwear.