Bluetooth 5.2, supports serial port name change (see HY5066TWS module user manual), supports one-click pairing, supports AUX insertion into the box without disconnection, power on, o call,default volume is maximum, with volume synchronization TX, RX, GND: TTL serial port configuration 9600, N, 8, 1 At 24V4A, the maximum output power is 2x50W;At 19V4A, the maximum output power is 2x40W;8-24V power supply, with reverse connection protection, supports power supply from notebook power adapter After pairing with , it lasts LED light: After setting up , the single board is always on and outputs the left channel, and the double board flashes and outputs stereo sound. Colour:As Shown Material:plastic Special button description: P/V-: Short press song, long press the volume decrease. +: Short press to play the previous song, long press to increase the volume. PLAY: Short press to play/pause Double-click to switch shareme (after setting up , the audio channel be switched online in a loop) Relative sub unit (right-left-stereo) Press and hold for 3S to reject/re-pair the phone (the host is valid) : Short press one-button pairing Double-click to switch EQ (9-band EQ cycle switching) Press and hold for 3S and be sure to release the switch prompt sound Press and hold 6S to clear the pairing list and restore EQ to default Due to different batches, there may be differences in product appearance and printed text, which not affect use Package Contents: 1 * Development Board 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.