Feature:BT 5.0 support button to turn off / boot, support serial port to change the tone volume and off, power on, no call function, the default volume is the largest TX, RX, GND: TTL serial port configuration 9600, N, 8, 1 the output maximum power 2x30W, power varies with voltage, DC power interface specification 5.5 x 2.5MM Suitable impedance: 4/6/8 ohm Power with reverse connection protection, support notebook power adapter power supply for ONE X2 Amplifier chip: TPA3118 Material: PC+metal colour: black Package Contents: 1 x Camera Lens Guards 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.