Marine Whistle with MIC 1.300W,130dB,400-700Hz; 2.an integrated,multifunction device 3.good ... ,stable performance Marine Whistle with MIC+Fog horn control 300WType: Dz-300WattDescription:an integrated device, containing MIC,Whistle,Fog horn control ... /ctnctn size:430*200*170mmItem: Microphone for electric whistleModel No: Dz-518GFrequency: 300-3 KilocycleImpedance: 300Ω Marine Whistle with MIC + Fog ...