Length side (mm): 520 Short side (mm): 260 Width (mm): 20 Thickness (mm): 1.0 Length tolerance: ±0.2mm or less Square angle: 0.1mm or less per 100mm Accuracy square angle: 0.1mm or less per 100mm Table scale long branch: Outer scale 50cm, inner scale 49厘米 表比例尺短分支:外尺度25厘米,内部比例23cm