Columbia Men's Trail Dryer Hat (Omni-Freeze ZERO) Constructed of 85% polyester/14% elastane fabric. Omni-Freeze ZERO fabrication delivers superior next-to-skin cooling. Omni-Wick EVAP delivers incredible sweat-dispatching properties for the coolest, driest wear. Omni-Shade UPF 50 provides premium protection from the sun. Hook and loop back adjustment.