COLONIAL-Rotary Blade Sharpener for 28mm Blades. Dual rotary blade sharpeners restore a razor-like edge for your rotary cutter. The disk lasts up to 6 months if used daily. For use with all brands of rotary blades. Not suitable for decorative edge. This wonderful little tool extends the life of your cutting blades. Remove small burrs and dull spots from the blade. Keep out of reach of children.