This Flattening Stone will keep your waterstones straight and flat for razor-sharp edges. It eliminates the “dish” that develops in waterstones over time and exposes a fresh cutting face for faster, more effective sharpening. This stone features coarse-grit silicon carbide that cuts quickly, and deep diagonal grooves that allow waste material to easily escape. For waterstones only. Measures 9" x 3" x 3/4".