84% Polyester, 16% Elastane Imported Under Armour’s mission is to make all athletes better through passion, design and the relentless pursuit of innovation Where we started? It all started with an idea to build a superior T-shirt The technology behind Under Armour's diverse product assortment for men, women and youth is complex, but the program for reaping the benefits is simple: wear HeatGear when it's hot, ColdGear when it's cold, and AllSeasonGear between the extremes. HOW TO MEASURE CHEST: Place the tape measure under your arms at the fullest part of your chest, wrap around your body until your fingers meet and mark the measurement.WAIST: Measure around your natural waistline. Be careful not to squeeze too tight to allow give. TALL Sizes: All tall sizes are 2 Inches longer than regular sizes. Sleeve lengths are adjusted proportionately depending on silhouette