Digital Light or Lux Meter Used for Measuring Brightness and Light Intensity of School, Lab, Office, Stadium, Theatres Along with Calibration Certificate by Testo Model: 540 (Range: 0~99999 Lux) - - Amazon.com
Pocket-sized lux meter - testo 540 - Kelfos Instruments India Pvt. Ltd.
Testo 540 Digital Light Tester illuminance Meter Lux Meter | eBay