Double-honed for extreme sharpness, OLFA® 25 mm Extra Heavy-Duty Ultra-Sharp Black Snap-Off Blades are 25% sharper than standard OLFA® silver blades. Manufactured from high-quality Japanese carbon tools steel, these blades are long lasting and durable. Choose Extra Heavy-Duty Blades for applications requiring superior sharpness. Seven segments per blade deliver a fresh new edge quick and easy. Use OLFA® 25 mm Extra Heavy-Duty Ultra-Sharp Black Snap-Off Blades for cutting nylon, rope, high-pressure laminates, expansion board and more.