Backer-On Rock-On Star Flat Head Cement Board Screws provide superior performance when attaching fiber cement backer board to wood or light gauge steel. Their patented serrated head design ensures flush seating at any angle, along with a smooth tile surface and easy 1-handed installation with the Star drive bit. Enjoy corrosion-resistant protection thanks to Climacoat finish, perfect for high-moisture areas like showers, countertops, and floors, and confidently install with a standard impact or drill/driver!