Alarm horn Siren 220V: fitted for alarm system,police firfighter ambulance Tone : yelp yelp2 wail hi-lo,horn, engineering etc alarm horn Siren 220V (alarm,speaker)Electronic source is AC220VBe fitted for alarm system:police firfighter ambulanceTone : yelp,yelp2, wail, hi-lo,horn, engineering,siren.