EW3-M bridge loudspeaker with automatic siren - 24V with microphone *Approved electronic whistle with loudspeaker *Integrated diaphragm control panel and electronic controller. *New ultrasonic heating system for improved acoustic membrane performance. *Complies with international COLREG 1972 IMO Class IV regulations with RINA, LLOYD'S REGISTER MCA, BUREAU VERITAS, NMMA and BSH approvals. *Includes mounting kit.