With the Sky Quality Meter, you can also get an accurate picture of the level of light pollution affecting your observing sites and how it is changing.
Often, amateur astronomers are unwittingly only able to determine the "quality" of a particular observing site subjectively. The current physiological state of the observer prevents an objective assessment, which is why instrumental monitoring is important, not only to help us choose the most suitable observing sites, but also to track changes and trends in sky quality over time.
The Sky Quality meter (L) version has a built-in objective lens that refines the measurement to a narrower 20° angle range, but it can also read not only sky quality but also the current ambient temperature in °C or °F. It can also be connected to a router via an ethernet connection, so you can read out its readings over the internet. It does not have a display and can only be read by the application.