31 PRECISION CRACK WIDTHS (mm): 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5, 0.55, 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.9, 0.95, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0, 5.5, 6.0, 6.5, 7.0. METRIC RULE: 0 cm - 16.5 cm, 1 mm tick-mark resolution. COEFFICIENT OF THERMAL EXPANSION (α): 70 µm/m/°C from -30 °C to +30 °C.NO PARALLAX: Bottom-printing virtually eliminates parallax and measurement distortion