The UA Iso-Chill ArmourVent Stretch Hat by Under Armour was designed to keep your head cool. It features special vents that allow the hot air out, but are small enough that the suns rays won't be an issue. The ArmourVent Technology delivers ultimate breathability in a light, stretchy, durable & fast-drying fabric that wicks away sweat and keeps you dry. The Iso-Chill sweatband & front panel lining helps disperse body heat, making it feel cool to the touch. The UA Iso-Chill ArmourVent Stretch Hat features a pre-curved visor & structured front panels that maintains shape with a low profile, classic fit.