Columbia Zero Rules Short Sleeve Tech Tee Top  (Colum Grey 039)COOL ADVENTURESMade for your most dynamic aerobic activity, this technical shirt beats the heat with our sweat-activated cooling technology.DRY AND PROTECTIVEUltra-wicking, cooling fabric manages sweat by reacting with your sweat to lower the material’s temperature. UPF 30 provides sun protection. Features Omni Freeze Zero - a unique fabric that release heat to help you feel cooler.Wear as a technical baselayer, or as a comfy t-shirt!