Take control of styling with the Centrix® Heat Boss thermal brush Styling fine hair? Keep the Heat Force Dial OPEN allowing heat to escape Styling medium to thick hair? Keep the Heat Force Dial CLOSED, trapping the heat in Styling thick, coarse hair? OPEN true Heat Force Dial, on high heat, point dryer nozzle down the Lux Barrel, increasing the heat temperature, CLOSE the dial and style away!