The combination oil stone with one thick-grit-size face for rough grinding and the other fine-grit-size for finishing, such an sharpening stone is made of the black  , brown Alumina oxide and white Alumina oxide with the Vitrified bond, The combination sharpening stone has got the advantages of easy carrying, quick sharpening, suitable hardness and long life, it can be used for grinding all of various manual cutting tools.

new sharpening stone