Straight Edge Flatness Tolerance 0.003 mm Calibration Certificate Not Certified Straightness Tolerance Not Applicable Parallelism Tolerance 4 micron Thickness Not Applicable Coating Not Applicable Flexibility Rigid Edge Style Square Color Green Backing Material Not Applicable Finish Not Applicable System of Measurement Metric/SAE Includes Case Length - SAE 20 in Length - Metric 500 mm Width - SAE 1 3/16 in Width - Metric 30 mm Magnetic Nonmagnetic Material Magnalium