Sanding paper panel is built in 8 vent holes and 1 positioning hole, making the sandpaper close to the panel. The center hole has a positioning fuction. Technical Parameter: 1.Center height: 25mm, Sandpaper granularity: 100 #, the other type of sandpaper is available according to the different requiements of the work-piecesand processing surfaces; 2.The Sanding table(effective area: 120 X 120mm)is molded with accuracy of 0.02mm scale line, that's great helpful for grinding precision of work prieces, including with wood, engineering plastics, soft metals(aluminium, copper, etc); 3.Machine size: 310mm*130mm*100mm