Invaluable aid for the reduction of noise levels within classrooms, exam settings, libraries, corridors and many other areas where noise is a problem. A great visual aid, which can also be used for the hearing impaired, and to teach voice projection. Can also be used for Road Safety activities. Using the recognisable traffic light system, will help with classroom management strategies as an automatic visual alert, which can be complemented by an audio 'quiet please!' or siren alert, when noise levels become too high. An adjustable sound level meter controls the decibel level from 40dB-120dB. Table or wall mountable (brackets included). Mains or battery powered. Measures 440 x 110 x 130mm.