With Bluetooth receiver amplifier card, AMP board is entitled with high performance according to rule. Support 18650 battery power, amplifier module keeps long service life so that you can use for a long time. Meanwhile, such audio amplifier board supports USB charging function, which is easy to use in the practical life. Via precision craft by many experts, this audio part is made of materials in high quality. AMP board's installation is simple, which does not require particularly complicated operations. Item Type: : Digital amplifier board Chip Model: Pam8403 Transmission Distance: Up to 20 m(unblocked) Channel: 2 Maximum Power: 5w + 5w size:10 x 7 x 2cm Material:PCB colour:green Package Contents: 1 x Digital Bluetooth power amplifier board Only the above package content, other products are not included. Note: Light 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.