1,The calibration is clear and easy to read, no need to replace the main body in the measurement process.  2,T-type writing, 45 degree angle, square multifunctional woodworking, multifunctional markers, aluminum alloy thickening guide.  3,With magnetic bottom, the central locator can be connected to the iron surface extension table, thick aluminum alloy, good stability.  4,Can be used to determine the exact position of the center of the cutting plate, pin joint and assembly isochron plate.  5,Simple sliding rules are applicable to overlapping markers on the left and right sides of the rules. 6,The center is made of aluminum alloy, environmentally friendly and durable in use. Note: Due to the light and screen setting difference, the item's color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement. Sold by-Minnanxin