These blades are made of special quality steel for unparalleled sharpness and superior edge retention. Cuts twice as long as the Olfa standard 45MM Rotary Blade. The extra strength and longevity makes the Endurance blade perfect for marathon quilting, sewing and crafting. Olfa 45mm endurance blade single pack, cuts twice as long as the standard 45mm Olfa rotary blade, for the RTY-2G, RTY-2DX, RTY-2NS, and RTY-2C rotary cutters.