Anyone who already owns an Ultra Corn Plane and needs a sharp replacement blade. It isn't a starter purchase on its own, since it requires the corn plane's blade holder to use.

A corn plane only works as well as its blade -- once it dulls, it takes more pressure to shave away the same amount of callus, which is exactly when slips and injuries become more likely. Replacing the blade before it gets to that point keeps the tool doing its job the way it's meant to.

Remove the dull blade from the Ultra Corn Plane's blade holder and replace it with a fresh one, following the holder's release mechanism. Use only on skin that's been softened in warm water first, drawing the blade across corns or calluses in short, light strokes -- never on dry or healthy skin, and never with heavy pressure.

Keeping a fresh blade on hand means the corn plane keeps cutting cleanly instead of dragging, which is both more effective and, somewhat counterintuitively, safer -- a sharp blade needs less pressure to do its job than a dull one does. The obvious limitation is that these are a refill, not a standalone product, and they're still a cutting implement that needs the same careful handling and precautions as the tool itself.