Due to the presence of special grooves, the stones on the aluminum blanks are fixed firmly. Aluminum blanks provide additional strength and rigidity in comparison with a plastic blank. Size of the blank - 160 x 25 mm, thickness 4 mm. Aluminum blanks for stones and leather 155x25mm with a bevel of 45 degrees. They allow you to clamp stones more securely and also protect them from damage. There are 5 aluminum blanks in this set