Werma signaltechnik continuous tone signal horn 108db werma signaltechnik 57005255 the werma signaltechnik 57005255 is a 24v dc continuous tone signal horn in an attractive housing and with impressive sound output with up to 108db this electronic horn is also safe and reliable in large machine halls and in areas with high ambient loudnessaudible signals are used when signalling with light is insufficient or unsuitable in industrial environments signal horns warn for example against