The four different functions; police yelp, engine noise, police siren and fire department siren can each be triggered by pressing the pushbutton. The respective function is immediately switched off by pressing the button repeatedly. The auto switch-off function is triggered after approx. 18 seconds. 2 standard AAA type batteries are included. The packaging is designed with an opening so that the module can be tested before purchase. The module is suitable for all MAN, Scania and MB Arocs lorries as well as MB Sprinter and Unimogs (not included).