... -4.0mm Weight: 1ct for 5pcs, 1ct for 7pcs, 1ct for 8pcs, 1ct for 9pcs, 1ct for 12 pcs, 1ct for 17pcs etc. Grade: YWD ... stability, applied to make tools for sawing all kinds of hard stone and concrete, also suitable for geological drills. YWD 2180 complete ... octahedron, good diaphaneity, high impact strength and thermal stability, suitable for high grade cutting, drilling, and grinding tools. YWD 2160 ...