Communication:  Wireless  Distance: over 30M Frequency:  UHF Material: Metal Model Number:  AK-100 Set Type:  Transmitter Sets  Style:  Handheld Microphone Transducer:  Dynamic Microphone  Use: Karaoke Microphone   Product Description Audio Frequency: 40-20KHz Dynamic Range:  95dB System Distortion:  0.5% Signal-to-Noise Ratio: <90dB Operating Range:  30M Frequency Channels: 8 channels Transmitter: Frequency Stability: + - 0.005% RF Output Power:  30mW Spurious Rejection: 40dB Power Supply: 2 * 1.5V AA battery (heandheld microphone), 450mA Li-batter for receive  1) LCD Screen: Display: Frequency, Battery power, Signal, etc.  2) Power Switch: ON / OFF  3) Frequency button: Press-to-change frequency of handheld microphone. Receiver frequency will change automatically.  4) Battery: 2 pcs AA battery supply power. Receiver: Li-battery: 450mA (4-6 hours)  Low power light USB interface  RF / AF light power switch