Granite square to be used to detect, measure, crossed, equipment installation, construction of industrial engineering. Granite at right angles to foot, also known as marble square, as the name suggests that the material is a granite square, the product and other granite products, using high quality "Jinan Qing" stone machined and made of hand-grinding. Granite foot rectangular black shiny material, structural precision, even texture, good stability, high strength, high hardness, heavy-duty and under the general temperature maintaining high accuracy, granite square with no rust, acid and alkali , wear resistance, magnetization, the same type and other advantages. 

 Granite square features and advantages: 
 Uniform a rock by a long-term natural aging, organizational structure, a very small linear expansion coefficient, internal stress completely disappeared, no deformation, so high precision. 
 2, good rigidity, high hardness, wear resistant. 
 3, granite right angle ruler are not afraid of acid, alkaline liquid material erosion, and will not rust, do not need oiling, easy to stick dust, maintenance, easy maintenance, long service life. 
 4, no scratches, not a constant temperature to prevent temperature measurement accuracy can be maintained at room temperature. 
 5, granite rectangular device is not magnetized, measurements can move smoothly, without Zhise sense, free from damp impact, the plane weighed 


 Granite rectangular device Specifications (mm): measurement face flatness or straightness um base surface flatness or straightness of the face of the base surface perpendicularity um um