Studio Projects C4 MKII matched pair - studio quality stereo microphone system, modular design, interchangeable capsules (omni, cardioid, hyper-cardioid), switchable -10/20dB pad/hi-pass filter (75HZ or 150Hz), transformerless output, frequency response: 40Hz-20kHz, output impedance: <200ohms, sensitivity: 12m V/Pa, max SPL: 150dB.