... switch 3,high quality Digital llluminance meter Features 1,Light-measuring levers ranging from 0.01 lux ,repeatedly 2.High Accuracy and ... indicates 20 lux ,200 lux ,2000 lux and 20,000 lux ranges ,respectively .3.Power Switch :The power switch key turns the illuminance meter ON ... meter to resume taking measurement s,5.Range Switch :Pressing the range key changes 20 lux,200 lux,2,000 lux and 20.000 lux ...