Features : Transmitter Operating voltage: 5V Frequency range: 2.403-2.478ghz Delay time: 24ms Channel interval: 1MHz Transmitting power: 4dbm Receiving and sending distance: > 10m 360 degrees Acceptance sensitivity: - 85dB Headset Operating voltage: 3.5-4.2v Working current: 75ma (max) Capacity of lithium battery: 1100mah Continuous working time with lights: > 9h Continuous working time without lights: > 11h Charging time: < 3H Frequency range: 2.400-2.483ghz Channel interval: 1MHz Transmitting power: 4dbm Sampling frequency: 48Khz Modulation mode: FSK Acceptance sensitivity: - 85dB Signal to the noise ratio: 85dB Speaker diameter: 50mm Speaker impedance: 32 ? Frequency response: 20-20KHz Microphone specification: 6022 Microphone sensitivity: - 37db ± 3dB Microphone directivity: omnidirectional Microphone frequency response: 100hz-8khz