Features: In modes, only the host will emit the sound of a microphone. In modes, due to limited resources, the decoding of FLAC songs on the USB drive may, which is not the case in non modes. Connection method: Power on two product while Bluetooth-compatible is not connect and USB are not inserted! Long press and hold the microphone adjustment knob of one of the product for more than 3 seconds, and the red indicator light will start flashing, indicating that you are searching for a matching box. After successful pairing, the Indicator light for this product remain for the left channel, while the indicator light for another product flashes on for the right channel. After successful pairing, the pairing function can work normally in Bluetooth-compatible, USB, and modes. Cancellation method: Long press the microphone adjustment knob of one of the product for more than 3 seconds, and the red indicator light will turn off, indicating that the function has been cancel. Clearing pairing record: After pairing, both the host and slave will record, making it difficult for a third party to pair successfully and requiring a clear code. Long press the music adjustment knob for more than 3 seconds to clear pairing record. Specifications: Material: Electronic Component Input: 8-36VDC Chip: BP1048B2 Bluetooth-compatible Distance: 15Meters Decoding Format: MP3, WAV, FLAC,(The bit rate is less than 1500kbps) Microphone Interface: Double 6.35mm Size: As Shown Type: 1/2 Note: Please allow 1-2cm errors due to manual measurement, make sure that you do not mind before you order. Due to the difference between different monitors, the picture may not reflect the actual color of the item. The cover needs to be assembled by yourself; Delivery without USB cable and cable. Package includes: 1x Karaoke Reverberation Board Front Stage Effector