The Blackwing One-Step Long Point Sharpener Replacement Blades is a welcome addition to the line. The set comes with three replacements made with German steel, designed to bend to the One-Step sharpener\’s unique concave shape. Replacement Instructions: To replace your sharpener\’s blade, simply unscrew the worn out blade from the sharpening unit, making sure to keep the nut and screw in a secure location.Set the old blade aside and align the new blade on the sharpening unit. Replace the screw and nut, and tighten until secure.