PRECISE; The Testo 545 optical light meter is the ideal instrument for efficient and accurate determination of illuminance of all common light sources according to the V-lambda curve | CONVENIENT; Thanks to automatic calculation and display of time and point averages, as well as audible alarm sounds, the luminance meter achieves fast and reliable results | DECISIVE; The light metering leads to productivity, well-being and health, which makes it a decisive factor, especially in offices and other working environments | LED COMPATIBILITY; The light meter for LED offers a wide range of applications and is compatible with all commercially available LEDs, except for single-color blue LED | APP CONNECTION; Conveniently display graph history, and view, store, and document all measured values directly from your testo digital lux meter on your Smartphone and Tablet - or use them as a second display