Martindale LM192 Light Meter 
General purpose light meter
Auto and manual ranging to 200,000 lux, 20,000 fc
Resolution to 0.1 lux
CIE photopic standard
Hold, Min and Max functions
Auto power off & low battery indication
LCD display with backlight
 The LM192 is a high quality general purpose light meter ideally suited to ensuring that office and commercial building lighting achieves the required levels for a healthy working environment. It provides readings up to 200,000 lux with a maximum resolution of 0.1 lux in the 200 lux range. The tough design makes it suitable for all working areas and the intuitive layout with detachable light sensor makes it easy to take accurate and reliable measurements in all types of application.
For accurate measurements with a wide range of light sources, the instruction manual provides a conversion chart for different light wavelengths.
The LM192 light meter is able to operate for approximately 80 hours continuously and has an auto power off (after 30 minutes) function that can be disabled for longer term Min/Max monitoring.