Olivia Garden's HeatPro Thermal Round Brush has copper ceramic technology, exclusive nylgard high heat resistant bristles, a patented extra large vent barrel and tourmaline ionic technology. Specifically designed to withstand the extreme high heat temperatures generated by today's most powerful blowdryers. Exclusive Nylgard bristles provide heat resistance up to 290°C. Copper ceramic technology provides ultra fast drying. Tourmaline ionic technology enhances cuticle hydration, eliminates frizz & flyaways. Made of high grade polycarbonate. Proprietary barrel-hole pattern for greater airflow, less drying time & faster styling. Anti-static & ultra lightweight. Vented cap design keeps top of brush head cool & boosts ventilation for faster drying. Design patent protected effortless grip ergonomic handle. Diameter: 42 mm