1: High-end audio experience 2: Protection mechanism: over temperature, over current, short circuit, anti-static protection 3: Features: Support APP. Modify the bluetooth name, password settings, prompts, Sound volume adjustment, on/off prompt sound, sleep aid, sound effect selection + custom sound effect, U disk playlist, volume indicator brightness adjustment. 4: Power amplifier chip: TPA3118 5: Multi-function knob, 360-degree stepless tuning, with volume level indication. Model: -R302 Name: 2.0 channel 30WX2 stereo with high and low adjustment Bluetooth audio power amplifier Power amplifier chip: TPA3118 Bluetooth version: 5.1 Audio input: Bluetooth+AUX+U disk+USB sound card Audio output: left channel 30W + right channel 30W Adapter power supply: DC9-24V, equal 3A (can not be connected to AC) Adapter speaker: 10-50W, 4-8Ω Volume adjustment: multi-function knob, 360-degree stepless tuning, with volume level indication. Click: Play/Pause Double click: mode switch (Bluetooth/U disk/AUX) and hold for 1 second: turn on/off Rotation: adjust the volume Protection mechanism: over temperature, over current, short circuit, anti-static protection Features: Support APP. Modify the bluetooth name, password settings, prompts Sound volume adjustment, on/off prompt sound, sleep aid, sound effect selection + custom sound effect, U disk playlist, volume indicator brightness adjustment. Product size: 81x81x34mm Product weight: net weight 77g Color:Black Material:plastic Package Contents: 1 * Amplifier 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.