2.4G Wireless Microphone Headset, 98ft Range Receiver Headset Mic, Handheld Mic and Collar Clip 3 In 1 Professional Voice Amplifier Headset Microphones for Karaoke Speaker PA System Teaching Working Voltage: 3.3V-5V Working Current: Maximum 100mA Environmental Temperature: -15~65 degrees Celsius Frequency Range: 2.4-2.483GHz Work Channel: 26CH Modulation Method: GFSK Baud Rate: 3Mbps Channel Interval: 3MHz Transmit Power: -10~18db Receiver Sensitivity: -80db Delay Time: 12.5ms Sampling Rate: 48KHz * 16bit Signal to Noise Ratio: 90db Distortion: 0.5% @ 1kHz Dynamic Range: 90db Left and Right Channel Isolation: 50db Transmit Frequency: 2.4G wireless microphone Microphone Type: Unidirectional (heart-shaped) condenser microphone Frequency Response: 20-20KHz Power Supply: 400mAh rechargeable battery Charging Time: About 2.5 hours Usage Time: About  6 hours Wireless Coverage Distance: About 40m/131ft (in open areas) Product Style: 1 Receiver with 1 Microphone, 1 Receiver with 2 Microphones (optional) Microphone Size: 2.5 * 1.5 * 21.5cm/1 * 0.6 * 8.5inch Receiver Size: 2.5 * 1.5 * 6.5cm/1 * 0.6 * 2.6inch Microphone Weight: 20g/0.7oz Receiver Weight: 13g/0.5oz