Product Detail Acoustic Operating Principle: Pressure Gradient Directional Pattern: Cardioid Frequency Response: 20Hz - 20kHz Sensitivity @ 1 kHz into 1 kOhm: 33.5 mV/Pa Rated Impedance: 50 Ohms . The "Blue Microphones Baby Bottle Cardioid Condenser Mic" is best product for you. We recommended Blue Microphones Baby Bottle Cardioid Condenser Mic