No need to loose your breath trying to blow on this whistle. This one is completely electronic and made of metal. Just push a button and out comes a louder whistle than even a traffic cop could blow. Great for referees, policeman, traffic cops, tour guides, umpires, sport trainers, military trainers, dog handlers, life guards. Also useful as a personal security device, hailing taxis, rounding up the kids on a playground or as an emergency warning device. And because you never have to put your lips on it there's no chance of spreading germs if you need to share it with someone. Compact size means it fits in your pocket or on a key chain just as easily as a normal whistle. Just push a button for a traditional super high 120 decibel whistle sound. Includes four LR44 or AG13 1.5VDC batteries.