There is a button for switching on and off and a button with which you can display the maximum sound level. To the reset before a new measurement, simply press and hold both buttons simultaneously.
The battery block needed is included, a manual but unfortunately not - but after a brief try one knows all the functions.
It is nice that the brightness sensor reacts very quickly and the display as soon as one goes out of direct light, is illuminated in blue - hence the display is easy to read.
I hope my review was for your buying decision a little help ?! :)
