SM137 Cardioid Condenser Instrument MicrophoneThe Shure SM137 is a versatile, flat response cardioid probe microphone with an ultra thin diaphragm. Its frequency response combines smooth high end and tight, controlled low end. A 15 dB pad provides natural, consistent sound reproduction in both acoustic and high volume performance applications. Product Features Electret Condenser Cardioid Microphone Ultra thin diaphragm for smooth high end and tight, controlled low end Transformerless Class A