For classic styles, you need tried-and-true styling tools. The ghd Curve 1-Inch Classic Curl Iron updates a recognizable tool with 21st century features: ultra-zone technology, an advanced ceramic coating and a cool tip that makes styling easier on your hair and your fingertips. Ultra-zone technology is a pretty ingenious development. What it does is maintain the Classic Curl Irons barrel at a constant temperature of 365 degrees Fahrenheit. But it also detects when adjustments are needed based on which section of hair its curling. It automatically changes its temperature to give you gorgeous curls while minimizing the risk of heat damage.