Features    1.The PD Meter is a digital precision optical instrument used to measure distance between human pupils in the process of optometry for fitting spectacles. 2.It employs precise optical structure,the line of light is very clear and precise measurement. The measurement results are displayed digitally, and the left eye and right eye measuring values are displayed separately. 3.Simple and rapid measuring operation, and free operation of the direct PD adjustment lever are possible. Combining with the adjustable viewing distance selecting lever for measuring all kind of the viewing distances, the PD measurement is simple and precise. 4.When the measuring operation is finished, the auto power off and memory function, enable to save the power and not to lose the data. 5.It can also be used in monocular the left eye and right eye separately.    Parameter    Effective range of measurement: binocular pupillary distance:45-82mm left or right pupillary distance:22.5-41mm Indication error: ≤0.5mm Distance of target:30cm& 65374;40cm Power:Rechargeable battery Dimensions:220x160x55mm/8.6x6.3x2.1inch Weight:1kg/2.2lbs    Package Include    1×Rechargeable digital PD Meter 1×Power adapter