Features 1、Upgrated BT5.3, smooth and quick connection. 2、Support true wireless to form a wireless pair box, instantly becoming a left and right channel stereo sound system. (Need 2 Audio Amplifier Board) 3、Fine quality and clear sound. 4、Input AntiReverse protections, over temperature protections, over current protections, shortcircuit protections, antiStatic protections. 5、Made of fine quality material for long lifespan. Specification Main color: black BT: 5.3 BT distance: max. 15m Audio input: BT+AUX+U Disk+USB Sound Card Audio output: 30W PowerSupply: DC9-24Volt, 3A (cannot be connected to ACpower) Adapted speaker: 4-8 Ω, 5-30W Item size: 71 * 47 * 21mm / 2.8 * 1.9 * 0.8in Item weight: 50g / 1.8ounce Package size: 80 * 60 * 30mm / 3.1 * 2.4 * 1.2in Package weight: 76g / 2.7ounce Package List 1 * Audio Amplifier Board