1. Granite has long-term natural aging, uniform structure, minimal linear expansion coefficient, complete disappearance of internal stress, no deformation, and therefore high precision.

　　2. Good rigidity, high hardness and strong wear resistance.

　　3, not afraid of acid, sputum liquid erosion, will not rust, do not need oil, not easy to stick dust, maintenance, maintenance is simple and convenient, long service life.

　　4, no scratches, not subject to constant temperature conditions, can maintain the accuracy of temperature measurement at room temperature.

　　5, no magnetization, smooth movement when measuring, no stagnation, not affected by moisture,  the plane is well defined.