ouble-honed for extreme sharpness, OLFA 9mm Precision Ultra-Sharp Black Snap-Off Blades are 25% sharper than standard OLFA silver blades. These 9mm Precision Blades are manufactured from high-quality Japanese carbon tool steel. This blade is perfect for any application requiring superior sharpness. With 13 cutting edges per blade, a fresh new blade is readily available quick and easy. Long lasting and durable, OLFA 9mm Precision Ultra-Sharp Black Snap-Off Blades deliver precision cuts through wallpaper, vinyl, paper, foam board, caulking, cardboard, molding, and more.