Electromegaphone `` EM-7 ''.

Acoustic systems, passive or active, as well as electro-acoustic units, hearing aids, electric megaphones, intercoms ...Electric megaphonesElectromegaphone "EM-7" was produced from the beginning of 1979 on p / box A-3466 (Moscow Research and Production Enterprise "Volna"). The electric megaphone is designed to give voice commands for various ship operations, as well as for communication between the ship and the shore at a distance of up to 300 meters, as well as for other purposes.