ltem description from the seller
Basic Parameters:
Silent Control: Noise Reduction
Frequency deviation: ±11kHz
Frequency response: 80Hz-15kHz
Frequency stability: ±0.005%
Signal-to-noise ratio: >60dB
Distortion: 0.5% at 1kHz
Number of channels: Two channels
Sensitivity: -70dB M
Usage distance: Open area 50m
Receiver power supply: DC 12V/320mA
Transmitter power supply: AA battery
Transmission power: 20mW
Frequency range: 200MHz-270MHz
Output mode: Independent and mixed automatic selection