◆ 【ACCURACY MEASURE PUPILLARY】PD Meter is a precision optical instrument used to measure distance between pupils in the process of optometry for spectacles,It features direct point-sampling and high accuracy of orientation.
◆ 【ENERGY- SAVING DESIGN】The design of LED lamp-house and low-power consumption ensure the prolonged service life of batteries. And the Brightness of LED Is Adjustable. +2.0d Compensation for The Degree of Eyesight Is Available.
◆ 【TURN OFF AUTOMATICALLY】Turns off after 1 minute or you can press a button and shut it off. It stays on and drains the batteries. Store device flat side down, it will turn off automatically.
◆ 【LONG READING TIME】It does retain the readings on screen while it is on and even in memory when it is switched back on as long as the slide controls have not been moved.The didital PD Meter does have a reading which lasts approximately 10 minutes
◆ 【AC/DC Power Supply】2 AA batteries or chargeable battery dual use.