Using UHF 460-990 MHz band to avert interferencing frequency. Automatic frequency scan feature searches for available frequencies PLL system. Preset 16 non-interfered channels. The receiver support DC power supply and AA batteries. ALL using SMT, more stable function. High efficiency batteries consumption design, so the handheld could be in using for 5 hours continuously. Long est distance: 60m, Ideal distance: 40m. It is suitable for Erhu, Violin, Saxophone usage. Receiver Receiving Frequencies: 460MHz-990MHz Modulation Type: F3E OSC (Oscillator) System: PLL circuit Operating Distance: 40m (receiver in sight) De-dmphasis: 50u/sec Receiving Sensitivity: Sina> 30dB 10dBuV Squelch Sensitivity: 17dBuV +4 dBuV Signal / Noise Ratio: (flKHz = lmV) <0.8% Audio Output Level: (f40KHz) 400Mv Audio Frequency Response: 50Hz-20KHz +3 dB THD: (flKHz) <0.8% Output Impedance: 5K-10K ohms Power: DC9V/6V AA (1.5Vx2 Battery) Current Consumption: 9V/60mA 3V/100mA Dual l/4wave length rod antennas Antenna: Dual l/4wave length rod antennas Controls: Audio level volume channel select switch, ACT key Controls: ACT SEND (white), Power (red) Low power (orange), single (green) Transmitter RF Output Power: 10dB ? 1dB Spurious:-50dBm Modulation: 40K Pre-emphasis: 50usec Maximum Input Level: +2 dBV Input Impedance: 20K ohms THD: <0.8% (1KHz 100mV) Audio Frequency Response: 50Hz-20KHz +3 dB Operating Power Voltage: 1.5V Tpical 1.0V Minimum 2V MAX Current Consumption: 80mA Battery Life: 8 Hours (AAA Side battery) Antenna: Permanently attached 11 4 wave length wire Controls: Power Switch, 15dB Pad Switch Indicators: Power On (LED Flash) Low Battery (LED On when battery less than 1V) ACT (LET Flash)