1.Green Rechargeable Batteries It is Including 3 pcs 18650 lithium batteries, it can be directly charged, can work for 3-5 hours after charging for 2 hours, we advocate environmental protection, it can protect the environment more. 2.Adjustable Frequency: UHF frequency band transmits signal, 2 channels design for signal reception, signal enhancement, wirele microphone transmiion distance up to 30 meters. The frequency range is between 520-580MHz. Anti-interference function: The karaoke wirele microphone has the function of locking the frequency, so that the wirele signal can be connected stably without interference from surrounding signals. 3. Two Karaoke Microphones Can Be Used At The Same Time: Suitable For Party Speakers, It can be connected to any speaker with a MIC interface by connecting the wirele receiver, or it can be connected to the mixer as an extension of the wirele microphon.G-MARK wirele microphone provides clear, crisp sound quality. 4.G-MARK Exclusive Capsule: The microphone capsule developed by the G-MARK has sensitive sound and high degree of restoration. The silicone base is more shockproof and noise-proof. How to adjust the frequency: If both microphones are on CHN A or CHN B, they cannot be used at the same time. You only need to do the following:Turn off the microphone, pre and hold the microphone switch for 7 seconds, until the microphone is turned on, the channel will change from CHN A to CHN B, let it go.When they have two microphones on CHN A and CHN B, they can be used at the same time. When two microphones cannot be used at the same time: When the microphones are on channels A and B, they can be used at the same time. If both microphones are on channel A or B, they cannot be used it. Microphone type Picking up way heart pointingFrequency range 520-580MHzRF bandwidth 60MHzFrequency points 8Transmitting power 10mWFrequency response 50Hz - 18KHzDynamic range 96dBHarmonic radiation <-50dBcDistortion <0.1%Power supply mode One 1200mA lithium battery (3.7V) Frequency range 520-580MHzRF bandwidth 60MHz8 frequency pointsSignal to noise ratio 96dBReceive sensitivity -95dBm If there are multiple sets of products in the same environment, crotalk may occur (same frequency with the same ID code)Caused by the following steps, the pairing operation can be completely solved.1. Adjust the transmiion and reception to the shutdown state at the same time;2. Transmitter: Pre the power switch and the frequency hopping button simultaneously for about 4 seconds, the display will flash quickly.status;3. Receiver: Turn on the receiver power, the RF indicator flashes 4 times;4. Transmitter: Short pre the frequency hopping button to exit pairing.Power switch2. Frequency hopping switchPower switch2. RF LEDFrequency response 50Hz - 18KHzDistortion 0.05%Dynamic range 96dBReceive delay 2.5msPower supply mode 12000mA lithium battery (3.7V) Package List: 1 Wirele Receiver, 2 UHF Wirele Handheld Microphones, 1 Power charge cable, 2 Roll Rings, 1*18650 Battery 1 x User Manual