Features include: These special files are manufactured by electroplating diamond grit in position on precision forged and ground steel blanks.The evenly distributed,long-lasting and sharp layer guarantees a high filling performance. Diamond rifflers are suitable for filling hardened steel and carbide metals in the manufacture of cutting dies,punching and press tools,etc.For easy access to hard to reach places. Diamond needle files are available in 3 grit sizes:D91,D126 and D151