Working distance.........................................................................0.67m
Adjustable range of streak...................................................3mm~20mm
Streak rotation...............................................................................360°
Illumination source............................................3.5V/2.5W Halogen bulb
Input voltage...................................................AC220V/50Hz;110V/60Hz
Power(main body)..............................................Li+battery pack DC3.7V

Temperature...........................................................5°C~40°C
Relative Humidity....................................................30%~75%
Atmospheric Pressure..................................700hPa~1060hPa
Power.....................................Charger: AC100-240V, 50-60Hz
                                                    Retinoscope: DC 3.7V Li + Battery