The BX-4 is a Bluetooth receiver for the Bluetooth 4.0 chip. This chip can make the sound quality better and more compatible. Simply plug the 3-pin card into the mixer or active audio, and then use the Bluetooth function to wirelessly transmit to devices such as smart phones and PADs. By tapping the STEREO-LINK button, the BX-4 can be paired with another BX-4 (in the case where a BX-4 has been paired with a Bluetooth device such as a mobile phone or tablet) to transmit a signal to the audio signal. Product parameters: Version: Bluetooth V4.0 Power supply: 3.7V lithium battery power supply Working current: ≤30mA Temperature range: -40℃-+80℃ Wireless transmission distance: 10m Sensitivity: -80dBm(0.1%) Frequency range: 2.4Ghz-2.480Ghz Signal to noise ratio: ≥75dB Distortion: ≤0.1% Charging method: USB charging Standby duration: 50 days (in ) Working hours: 10 hours (theoretical) Colour: Black Material: Aluminum Alloy Package Contents: 1 x Audio Receiver 1 x USB cable (Due to different product batches, the appearance , which does not affect the use) Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.