·Operates a single 100/1150watt speaker. ·Designed with new tone procedures. comprehensively improve warning effectiveness. ·8 primary operating modes: Radio, Aux, Wail, Yelp, Pir, Air-horn override, User selectable tone and push-button mannul override ·With exterior trigger function: when the siren is turned on. Wail, Yelp and Pir could be activated from steering wheel horn ring, convenient for driver to operate. ·Polarity protection. ·Double-color backlight indicator adapts night operation.·Tones are ready to be customised. ·With light control function ·Warning sound volume adjustable.