The class 2 outdoor sound level meter PCE-428-EKIT-ICA, from the field of environmental measurement technology, is an optimal sound level meter for measurements at workplaces, construction sites, in traffic, airports, etc. The outdoor sound level meter is equipped with an octave band frequency filter. Optionally, the outdoor sound level meter can be upgraded with a 1/3 octave band filter. The additional kit for outdoor sound measurement makes it possible to measure outdoor noise with a sound level meter over a long period of time, even in the rain.