Jammin Pro TWINPROMKII Wireless Microphones and Wireless Microphone Systems Frequency Range: 530MHz-548MHz,Frequency Control: PLL,Frequency Precision: +/- 5ppm&lt;10kHz Frequency Steadiness: +/- 0.005%,Number of Frequencies: 71,Modulation Mode: FM Number of Channels: 2 Channels, Frequency Spacing: 250KHz,Frequency Response: 80Hz-18KHz(-3dB),Max. Frequency Deviation: +/- 45KHz