1. Magnification of Eyepiece: 15X; 2. Total Magnification: 18X; 3. Illumination: 2X 6V/12W halogen bulb; Measurement Range: 1. Radius of Curvature: 5.5-11mm; 2. Diopter: 30-60dpt; 3. Readings radius: 0.02mm; 4. Diopter: 2.25dpt; 5. Refractive index n used for compensation: 1.3375; 6. Minimum Surface required for measurement: r=5.5mm Φ1.65mm r=7.5mm Φ2.36mm r=11mm Φ3.36mm 7. Angle Measuring Disc: 0~180; 8. Input Voltage: 220V;