ghd Ceramic Vented Round Brush - 2.1" Barrel The size 4’s maxi barrel is best for long and extra long hair, or creating lots of volume in mid-length styles. Ceramic Vented Radial Brushes-The essential brush collection for a soft, high-volume blow dry. The ghd ceramic vented radial brushes deliver shape, volume and shine to your blow dry for a salon-fresh style. Hollow 2.1" diameter barrel-Vented ceramic barrel retains the heat of the hair dryer for faster styling. Soft touch handle-Non-slip handle with soft touch for styling control. Professional design-Hand finished.