Speaker size: 40mm Speaker impedance: 200 Speaker frequency: 20HZ-20KHZ Speaker sensitivity: 1003dB Battery type: lithium polymer battery Charging time: <3 hours Endurance time:> 15 hours Transmission Distance: No obstacle 10 meters 360 degrees Operating Voltage: VDC 3.2-4.2V Battery Capacity: 800mAh Charging Parameters: VDC5V= 1A Microphone Sensitivity: -42‡3dB Microphone Directivity: Omni-directional Low latency: <80MS