X-Life refill blades are precision-crafted of quality sharpened carbon steel so you can make the most detailed meticulous cuts knowing that the blade can stand up to the pressure. When elaborate detailed cuts need to be made the No. 11 Classic Fine Point knife blade is the blade to choose. Each blade is blue oxidized to prevent rust and increase durability. X-Acto No.11 Classic Fine Pnt X-Life Refill Blade Silver 500 / Box (Quantity)