A combination of several horn, electrical with different frequences.
NSN 6645-01-160-7707
NSN 5920-01-141-6885
NSN 5920-01-610-3494
NSN 5975-00-534-8756
NSN 6220-01-392-1429
NSN 4140-01-186-0463
NSN 6685-01-138-7525
NSN 5999-01-521-1113
NSN 5915-00-939-8864
NSN 5935-01-081-9399
NSN 6135-01-633-8502
NSN 6110-01-374-5710